WorldWideScience

Sample records for barrier limits transmission

  1. Photon-Assisted Transmission through a Double-Barrier Structure

    Energy Technology Data Exchange (ETDEWEB)

    LYO,SUNGKWUN K.

    2000-06-27

    The authors study multi-photon-assisted transmission of electrons through single-step, single-barrier and double-barrier potential-energy structures as a function of the photon energy and the temperature. Sharp resonances in the spectra of the tunneling current through double-barrier structures are relevant to infra-red detectors.

  2. Relativistic Double Barrier Problem with Three Sub-Barrier Transmission Resonance Regions

    CERN Document Server

    Alhaidari, A D; Jellal, A

    2010-01-01

    We obtain exact scattering solutions of the Dirac equation in 1+1 dimensions for a double square barrier vector potential. The potential floor between the two barriers is higher than 2mc^2 whereas the top of the barriers is at least 2mc^2 above the floor. The relativistic version of the conventional double barrier transmission resonance is obtained for energies within + or - mc^2 from the height of the barriers. However, we also find two more (sub-barrier) transmission resonance regions below the conventional one. Both are located within the two Klein energy zones and characterized by resonances that are broader than the conventional ones.

  3. WAVE TRANSMISSION AND REFLECTION DUE TO A THIN VERTICAL BARRIER

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A numerical method, the boundary fitted coordinate method (BFC),was used to investigate the transmission and reflection of water waves due to a rigid thin vertical barrier descending from the water surface to a depth, i. e. , a curtain-wall type breakwater. A comparison between the present computed results and previous experimental and analytical results was carried out which verifies the prediction of the BFC method. Wave transmission and reflection due to the barrier were computed, and the transmission and refiection coefficients were given in a figure.

  4. Resonant tunneling in a Luttinger liquid for arbitrary barrier transmission

    OpenAIRE

    Huegle, S.; Egger, R.

    2003-01-01

    A numerically exact dynamical quantum Monte Carlo approach has been developed and applied to transport through a double barrier in a Luttinger liquid with arbitrary transmission. For strong transmission, we find broad Fabry-Perot Coulomb blockade peaks, with a lineshape parametrized by a single parameter, but at sufficiently low temperatures, non-Lorentzian universal lineshapes characteristic of coherent resonant tunneling emerge, even for strong interactions. For weak transmission, our data ...

  5. 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.

  6. 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

  7. 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.

  8. Angular confinement and direction-dependent transmission in graphene nanostructures with magnetic barriers

    Science.gov (United States)

    Masir, M. Ramezani; Vasilopoulos, P.; Matulis, A.; Peeters, F. M.

    2010-01-01

    We evaluate the transmission through magnetic barriers in graphene-based nanostructures. Several particular cases are considered: a magnetic step, single and double barriers, δ -function barriers as well as barrier structures with inhomogeneous magnetic field profiles but with average magnetic field equal to zero. The transmission exhibits a strong dependence on the direction of the incident wave vector. In general the resonant structure of the transmission is significantly more pronounced for (Dirac) electrons with linear spectrum compared to that for electrons with a parabolic one.

  9. Barrier transmission map of one-dimensional nonlinear split-ring-resonator-based metamaterials: Bright, dark, and gray soliton resonances

    Science.gov (United States)

    McGurn, Arthur R.

    2013-10-01

    The barrier transmission characteristics of a one-dimensional chain of optically linear split-ring resonators (SRRs) containing a barrier composed of optically nonlinear split-ring resonators are studied. (This is an analogy to the quantum mechanical problem of the resonant transmission of a particle through a finite barrier potential.) The SRRs are idealized as inductor-resistor-capacitor-equivalent resonator circuits where the capacitance is either from a linear dielectric medium (optically linear SRRs) or from a Kerr-type nonlinear dielectric medium (optically nonlinear SRRs). The SRRs are arrayed in a one-dimensional chain and interact with one another through weak nearest-neighbor mutually inductive couplings. The transmission maxima of the SRR barrier problem are studied as they are located in a two-dimensional parameter space characterizing the linear mutually inductive coupling and the nonlinear Kerr dielectric of the SRRs of the barrier. The result is a two-dimensional map giving the conditions for the existence of the resonant-barrier modes that are excited in the transmission process. The various lines of transmission maxima in the two-dimensional plot are associated with different types of resonant excitations in the barrier. The map is similar to one recently made in McGurn [Phys. Rev. BPRBMDO0163-182910.1103/PhysRevB.77.115105 77, 115105 (2008)] for the resonant-transmission modes of a nonlinear barrier in a photonic crystal waveguide. The SRR problem, however, is quite different from the photonic crystal problem as the nonlinear difference equations of the two systems are different in the nature of their nonlinear interactions. Consequently, the results for the two systems are briefly compared. The transmission maxima of the SRR system occur along lines in the two-dimensional plot, which are associated with modes resonantly excited in the barrier. These lines of resonant modes either originate as a simple evolution from the resonant modes of the

  10. Intrapartum practices to limit vertical transmission of HIV.

    Science.gov (United States)

    du Preez, Antoinette; du Plessis, Engela; Pienaar, Abel

    2006-09-01

    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 region of the North West Province of South Africa were surveyed for their knowledge of safe intrapartum practices that can limit vertical transmission of HIV, consequently indicating which intrapartum practices prevail in the region. We used a quantitative survey design and collected data by means of a questionnaire and checklist. A purposeful availability sample of 31 midwives who work in all four hospitals in the province was used and a random sample of 401 obstetric records was audited. Data were analysed by means of frequency analysis, effect sizes and cross-reference. A slight majority of the midwives had sufficient knowledge to distinguish between risky and safe practices. However, safe intrapartum practices are not always carried out and this raises concerns. 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. PMID:25875244

  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. Transmission Level High Temperature Superconducting Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Gary [SuperPower, Inc., Synectady, 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.

  13. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes.

    Science.gov (United States)

    Kumar, Ashutosh; Heilmann, M; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M; Christiansen, Silke H; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained.

  14. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes

    Science.gov (United States)

    Kumar, Ashutosh; Heilmann, M.; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M.; Christiansen, Silke H.; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained. PMID:27282258

  15. Barrier layers against oxygen transmission on the basis of electron beam cured methacrylated gelatin

    Science.gov (United States)

    Scherzer, Tom

    1997-08-01

    The development of barrier layers against oxygen transmission on the basis of radiation-curable methacrylated gelatin will be reported. The electron beam cured gelatin coatings show an extremely low oxygen permeability and a high resistance against boiling water. Moreover, the methacrylated gelatins possess good adhesion characteristics. Therefore, they are suited as barrier adhesives in laminates for food packaging applications. If substrate foils from biodegradable polymers are used, the development of completely biodegradable packaging materials seems to be possible.

  16. 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.

  17. Transmission barriers for bovine ovine, and human prions in transgenic mice

    OpenAIRE

    Van Scott, Michael R.; Peretz, David; Nguyen, Hoang-Oanh B.; Stephen J DeArmond; Prusiner, Stanley B.

    2005-01-01

    Transgenic (Tg) mice expressing full-length bovine prion protein (BoPrP) serially propagate bovine spongiform encephalopathy (BSE) prions without posing a transmission barrier. These mice also posed no transmission barrier for Suffolk sheep scrapie prions, suggesting that cattle may be highly susceptible to some sheep scrapie strains. Tg(BoPrP) mice were also found to be susceptible to prions from humans with variant Creutzfeldt-Jakob disease (CJD); on second passage in Tg(BoPrP) mice, the in...

  18. Reflection and transmission of regular waves at a surface-pitching slotted barrier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The interactions between regular surface waves and a surface-pitching slotted barrier are investigated both analytically and experimentally.A quasi-linear theory is developed using the eigenfunction expansion method.The energy dissipation within the barriers is modeled by a quadratic friction factor, and an equivalent linear dissipation coefficient, which is depth-varying, wave-height dependent, is introduced to linearize the matching condition at the surface-pitching barrier.By comparing the theoretical results with laboratory experiments, it is shown that the present method can satisfactorily predict the variation of the reflection and transmission coefficients with wave height.

  19. A Closed Formula for the Barrier Transmission Coefficient in Quaternionic Quantum mechanics

    CERN Document Server

    De Leo, Stefano; Leonardi, Vinicius; Pereira, Kenia

    2010-01-01

    In this paper, we analyze, by using a matrix approach, the dynamics of a non-relativistic particle in presence of a quaternionic potential barrier. The matrix method used to solve the quaternionic Schrodinger equation allows to obtain a closed formula for the transmission coefficient. Up to now, in quaternionic quantum mechanics, almost every discussion on the dynamics of non-relativistic particle was motived by or evolved from numerical studies. A closed formula for the transmission coefficient stimulates an analysis of qualitative differences between complex and quaternionic quantum mechanics, and, by using the stationary phase method, gives the possibility to discuss transmission times.

  20. Transmission upper limit of band-pass double-layer FSS and method of transmission performance improvement

    Institute of Scientific and Technical Information of China (English)

    Minjie Huang; Zhijun Meng

    2015-01-01

    The transmission upper limit of a double-layer frequency selective surface (FSS) with two infinitely thin metal arrays is pre-sented based on the study of the general equivalent transmission line model of a double-layer FSS. Results of theoretical analyses, numerical simulations and experiments show that this transmis-sion upper limit is independent of the array and the element, which indicates that it is impossible to achieve a transmission upper limit higher than this one under a given incident and dielectric-supporting condition by the design of the periodic array. Both the applicable condition and the possible application of the transmis-sion upper limit are discussed. The results show that the transmis-sion upper limit not only has a good reachability, but also provides a key to effectively improve the transmission performance of a double-layer FSS or more complex frequency selective structures.

  1. Interaction of tide and salinity barrier: Limitation of numerical model

    OpenAIRE

    Suphat Vongvisessomjai; Phairot Chatanantavet2; Patchanok Srivihok

    2008-01-01

    Nowadays, the study of interaction of the tide and the salinity barrier in an estuarine area is usually accomplished vianumerical modeling, due to the speed and convenience of modern computers. However, numerical models provide littleinsight with respect to the fundamental physical mechanisms involved. In this study, it is found that all existing numericalmodels work satisfactorily when the barrier is located at some distance far from upstream and downstream boundary conditions.Results are co...

  2. Interaction of tide and salinity barrier: Limitation of numerical model

    Directory of Open Access Journals (Sweden)

    Suphat Vongvisessomjai1

    2008-07-01

    Full Text Available Nowadays, the study of interaction of the tide and the salinity barrier in an estuarine area is usually accomplished vianumerical modeling, due to the speed and convenience of modern computers. However, numerical models provide littleinsight with respect to the fundamental physical mechanisms involved. In this study, it is found that all existing numericalmodels work satisfactorily when the barrier is located at some distance far from upstream and downstream boundary conditions.Results are considerably underestimate reality when the barrier is located near the downstream boundary, usually theriver mouth. Meanwhile, this analytical model provides satisfactory output for all scenarios. The main problem of thenumerical model is that the effects of barrier construction in creation of reflected tide are neglected when specifying thedownstream boundary conditions; the use of the boundary condition before construction of the barrier which are significantlydifferent from those after the barrier construction would result in an error outputs. Future numerical models shouldattempt to account for this deficiency; otherwise, using this analytical model is another choice.

  3. 75 FR 359 - Guidance on Simultaneous Transmission Import Limit Studies; Notice Allowing Post-Technical...

    Science.gov (United States)

    2010-01-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Guidance on Simultaneous Transmission Import Limit Studies; Notice Allowing... provide guidance for performing Simultaneous Transmission Import Limit (SIL) studies. All...

  4. Assessing transmissible spongiform encephalopathy species barriers with an in vitro prion protein conversion assay

    Science.gov (United States)

    Johnson, Christopher J.; Carlson, Christina M.; Morawski, Aaron R.; Manthei, Alyson; Cashman, Neil R.

    2015-01-01

    Studies to understanding interspecies transmission of transmissible spongiform encephalopathies (TSEs, prion diseases) are challenging in that they typically rely upon lengthy and costly in vivo animal challenge studies. A number of in vitro assays have been developed to aid in measuring prion species barriers, thereby reducing animal use and providing quicker results than animal bioassays. Here, we present the protocol for a rapid in vitroprion conversion assay called the conversion efficiency ratio (CER) assay. In this assay cellular prion protein (PrPC) from an uninfected host brain is denatured at both pH 7.4 and 3.5 to produce two substrates. When the pH 7.4 substrate is incubated with TSE agent, the amount of PrPC that converts to a proteinase K (PK)-resistant state is modulated by the original host’s species barrier to the TSE agent. In contrast, PrPC in the pH 3.5 substrate is misfolded by any TSE agent. By comparing the amount of PK-resistant prion protein in the two substrates, an assessment of the host’s species barrier can be made. We show that the CER assay correctly predicts known prion species barriers of laboratory mice and, as an example, show some preliminary results suggesting that bobcats (Lynx rufus) may be susceptible to white-tailed deer (Odocoileus virginianus) chronic wasting disease agent.

  5. Beating oscillation and Fano resonance in the laser assisted electron transmission through graphene δ-function magnetic barriers

    Science.gov (United States)

    Biswas, R.; Maity, S.; Sinha, C.

    2016-10-01

    We investigate theoretically the transmission of electrons through a pair of δ-function magnetic barriers in graphene in presence of external monochromatic, linearly polarized and CW laser field. The transmission coefficients are calculated in the framework of non-perturbative Floquet theory using the transfer matrix method. It is noted that the usual Fabry-Perot oscillations in transmission through the graphene magnetic barriers with larger inter barrier separation takes the shape of beating oscillations in presence of the external laser field. The laser assisted transmission spectra are also found to exhibit the characteristic Fano resonances (FR) for smaller values of the inter barrier separation. The appearance of the perfect node in the beating oscillation and the asymmetric Fano line shape can be controlled by varying the intensity of the laser field. The above features could provide some useful and potential information about the light - matter interactions and may be utilized in the graphene based optoelectronic device applications.

  6. 75 FR 18497 - Guidance on Simultaneous Transmission Import Limit Studies for the Northwest Region; Notice of...

    Science.gov (United States)

    2010-04-12

    ... Energy Regulatory Commission Guidance on Simultaneous Transmission Import Limit Studies for the Northwest... in the Northwest region an opportunity to ask questions regarding the Simultaneous Transmission... on SIL studies \\1\\ and the December 16, 2009 Technical Conference ``Guidance on...

  7. 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...

  8. 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. PMID:27357921

  9. Photon exchange and entanglement formation during transmission through a rectangular quantum barrier

    Energy Technology Data Exchange (ETDEWEB)

    Sulyok, Georg, E-mail: gsulyok@ati.ac.at; Durstberger-Rennhofer, Katharina; Summhammer, Johann

    2015-09-04

    When a quantum particle traverses a rectangular potential created by a quantum field both photon exchange and entanglement between particle and field take place. We present the full analytic solution of the Schrödinger equation of the composite particle–field system allowing investigation of these phenomena in detail and comparison to the results of a classical field treatment. Besides entanglement formation, remarkable differences also appear with respect to the symmetry between energy emission and absorption, resonance effects and if the field initially occupies the vacuum state. - Highlights: • Full analytic solution for the transmission through a rectangular quantum barrier. • Transition from classical to quantum field is illustrated. • Entanglement as a unique feature of the quantized field treatment is emphasized. • Non-trivial entanglement between position and photon number for coherent fields. • Interaction with vacuum state peculiar to the quantized field treatment.

  10. 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

  11. Quantum Limitations on the Storage and Transmission of Information

    CERN Document Server

    Bekenstein, J D; Bekenstein, Jacob D.; Schiffer, Marcelo

    1990-01-01

    Information must take up space, must weigh, and its flux must be limited. Quantum limits on communication and information storage leading to these conclusions are here described. Quantum channel capacity theory is reviewed for both steady state and burst communication. An analytic approximation is given for the maximum signal information possible with occupation number signal states as a function of mean signal energy. A theorem guaranteeing that these states are optimal for communication is proved. A heuristic "proof" of the linear bound on communication is given, followed by rigorous proofs for signals with specified mean energy, and for signals with given energy budget. And systems of many parallel quantum channels are shown to obey the linear bound for a natural channel architecture. The time--energy uncertainty principle is reformulated in information language by means of the linear bound. The quantum bound on information storage capacity of quantum mechanical and quantum field devices is reviewed. A sim...

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

    NARCIS (Netherlands)

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

    1997-01-01

    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 su

  13. 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.

  14. Exact analytical evaluation of time dependent transmission coefficient from the method of reactive flux for an inverted parabolic barrier.

    Science.gov (United States)

    Chakrabarti, Rajarshi

    2007-04-01

    The paper demonstrates an elegant way of combining the normal mode analysis and the method of reactive flux to evaluate the time dependent transmission coefficient for a classical particle coupled to a set of harmonic oscillators, surmounting a one dimensional barrier. The author's analysis reproduces the results of Kohen and Tannor [J. Chem. Phys. 103, 6013 (1995)] and Bao [J. Chem. Phys. 124, 114103 (2006)]. Moreover the use of normal mode analysis has a better physical meaning.

  15. 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.

  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. Detecting differential transmissibilities that affect the size of self-limited outbreaks.

    Directory of Open Access Journals (Sweden)

    Seth Blumberg

    2014-10-01

    Full Text Available Our ability to respond appropriately to infectious diseases is enhanced by identifying differences in the potential for transmitting infection between individuals. Here, we identify epidemiological traits of self-limited infections (i.e. infections with an effective reproduction number satisfying [0 < R eff < 1 that correlate with transmissibility. Our analysis is based on a branching process model that permits statistical comparison of both the strength and heterogeneity of transmission for two distinct types of cases. Our approach provides insight into a variety of scenarios, including the transmission of Middle East Respiratory Syndrome Coronavirus (MERS-CoV in the Arabian peninsula, measles in North America, pre-eradication smallpox in Europe, and human monkeypox in the Democratic Republic of the Congo. When applied to chain size data for MERS-CoV transmission before 2014, our method indicates that despite an apparent trend towards improved control, there is not enough statistical evidence to indicate that R eff has declined with time. Meanwhile, chain size data for measles in the United States and Canada reveal statistically significant geographic variation in R eff, suggesting that the timing and coverage of national vaccination programs, as well as contact tracing procedures, may shape the size distribution of observed infection clusters. Infection source data for smallpox suggests that primary cases transmitted more than secondary cases, and provides a quantitative assessment of the effectiveness of control interventions. Human monkeypox, on the other hand, does not show evidence of differential transmission between animals in contact with humans, primary cases, or secondary cases, which assuages the concern that social mixing can amplify transmission by secondary cases. Lastly, we evaluate surveillance requirements for detecting a change in the human-to-human transmission of monkeypox since the cessation of cross-protective smallpox

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

    OpenAIRE

    P. Balachennaiah; M. Suryakalavathi; Palukuru Nagendra

    2016-01-01

    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 ...

  19. The global distribution and transmission limits of lymphatic filariasis : past and present.

    OpenAIRE

    Cano, J; Rebollo, MP; Golding, N.; Pullan, RL; Crellen, T; Soler, A.; Kelly-Hope, LA; Lindsay, SW; Hay, SI; Bockarie, MJ; Brooker, SJ

    2014-01-01

    Background Lymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination by 2020 and to guide elimination efforts countries have, in recent years, conducted extensive mapping surveys. Documenting the past and present distribution of LF and its environmental limits is important for a number of reasons. Here, we present an initiative to develop a global atlas of LF and present a new global map of the limits of LF transmission. Methods We undertook a systema...

  20. Investigating rate-limiting barriers to nanoscale nonviral gene transfer with nanobiophotonics

    Science.gov (United States)

    Chen, Hunter H.

    Nucleic acids are a novel class of therapeutics poised to address many unmet clinical needs. Safe and efficient delivery remains a significant challenge that has delayed the realization of the full therapeutic potential of nucleic acids. Nanoscale nonviral vectors offer an attractive alternative to viral vectors as natural and synthetic polymers or polypeptides may be rationally designed to meet the unique demands of individual applications. A mechanistic understanding of cellular barriers is necessary to develop guidelines for designing custom gene carriers which are expected to greatly impact this delivery challenge. The work herein focused on the relationships among nanocomplex stability, intracellular trafficking and unpacking kinetics, and DNA degradation. Ultrasensitive nanosensors based on QD-FRET were developed to characterize the biophysical properties of nanocomplexes and study these rate-limiting steps. Quantitative image analysis enabled the distributions of the subpopulation of condensed or released DNA to be determined within the major cellular compartments encountered during gene transfer. The steady state stability and unpacking kinetics within these compartments were found to impact transgene expression, elucidating multiple design strategies to achieve efficient gene transfer. To address enzymatic barriers, a novel two-step QD-FRET nanosensor was developed to analyze unpacking and DNA degradation simultaneously, which has not been accomplished previously. Bioresponsive strategies such as disulfide crosslinking and thermosensitivity were evaluated by QD-FRET and quantitative compartmental analysis as case studies to determine appropriate design specifications for thiolated polymers and thermoresponsive polypeptides. Relevant nanobiophotonic tools were developed as a platform to study major rate-limiting barriers to nanomedicine and demonstrated the feasibility of using mechanistic information gained from these tools to guide the rational design of

  1. Theoretical limit of repeater spacing in an optical transmission line utilizing Raman amplification

    Science.gov (United States)

    Nakashima, T.; Seikai, S.; Nakazawa, M.; Negishi, Y.

    1986-08-01

    The limit of repeater spacing is investigated theoretically for optical transmission lines utilizing stimulated Raman scattering to amplify the signal light. Achievable repeater spacing is numerically estimated on the basis of coupled power equations and measured fiber characteristics for various signal wavelengths and relative index differences. Three types of transmission line configurations are considered, i.e., utilization of forward only, backward only, and bidirectional amplification. In the third case, a transmission distance of more than 400 km is predicted for an input signal light power of 100 microW, a signal wavelength of 1.57 microns, and a pump power of 0.5 W using a fiber with a relative index difference of 1 percent for signal light amplification.

  2. Detecting differential transmissibilities that affect the size of self-limited outbreaks.

    Science.gov (United States)

    Blumberg, Seth; Funk, Sebastian; Pulliam, Juliet R C

    2014-10-01

    Our ability to respond appropriately to infectious diseases is enhanced by identifying differences in the potential for transmitting infection between individuals. Here, we identify epidemiological traits of self-limited infections (i.e. infections with an effective reproduction number satisfying [0 measles in North America, pre-eradication smallpox in Europe, and human monkeypox in the Democratic Republic of the Congo. When applied to chain size data for MERS-CoV transmission before 2014, our method indicates that despite an apparent trend towards improved control, there is not enough statistical evidence to indicate that R eff has declined with time. Meanwhile, chain size data for measles in the United States and Canada reveal statistically significant geographic variation in R eff, suggesting that the timing and coverage of national vaccination programs, as well as contact tracing procedures, may shape the size distribution of observed infection clusters. Infection source data for smallpox suggests that primary cases transmitted more than secondary cases, and provides a quantitative assessment of the effectiveness of control interventions. Human monkeypox, on the other hand, does not show evidence of differential transmission between animals in contact with humans, primary cases, or secondary cases, which assuages the concern that social mixing can amplify transmission by secondary cases. Lastly, we evaluate surveillance requirements for detecting a change in the human-to-human transmission of monkeypox since the cessation of cross-protective smallpox vaccination. Our studies lay the foundation for future investigations regarding how infection source, vaccination status or other putative transmissibility traits may affect self-limited transmission. PMID:25356657

  3. 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.

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

    International Nuclear Information System (INIS)

    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

  5. How well does a limited participation model of the monetary transmission mechanism match UK data?

    OpenAIRE

    Shamik Dhar; Stephen P Millard

    2000-01-01

    This paper analyses how well a 'limited participation' model of the monetary transmission mechanism is able to match important aspects of the UK economy. Given that the endogenous monetary policy rule being followed by the monetary authority is not explicitly modelled, the model might not be expected to match the correlations and variances in the data. However, subject to this caveat, the model is able to reproduce the stylised fact that there is little relationship between monetary aggregate...

  6. 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.

  7. 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...

  8. The international limits and population at risk of Plasmodium vivax transmission in 2009.

    Directory of Open Access Journals (Sweden)

    Carlos A Guerra

    more widely distributed than P. falciparum and is a potential cause of morbidity and mortality amongst the 2.85 billion people living at risk of infection, the majority of whom are in the tropical belt of CSE Asia. The probability of infection is reduced massively across Africa by the frequency of the Duffy negative trait, but transmission does occur on the continent and is a concern for Duffy positive locals and travellers. The final map provides the spatial limits on which the endemicity of P. vivax transmission can be mapped to support future cartographic-based burden estimations.

  9. Impact of Channel Asymmetry on Base Station Cooperative Transmission with Limited Feedback

    CERN Document Server

    Hou, Xueying

    2010-01-01

    Base station (BS) cooperative transmission, also known as coordinated multi-point transmission (CoMP), is an effective way to avoid inter-cell interference in universal frequency reuse cellular systems. To gain the promised benefit, however, huge feedback overhead is in demand to gather the channel information. In this paper, we analyze the impact of channel asymmetry, which is inherent in CoMP systems, on downlink BS cooperative transmission with limited feedback. We analyze the per-user rate loss of a multi-user CoMP system led by quantization. Per-cell quantization of multicell channels is considered, which quantizes the local channel and cross channel separately and is more feasible in practice. From both the analytical and simulation results, we provide a whole picture on various critical factors that lead to the performance loss. Specifically, we show that the per user rate loss led by limited feedback depends on the location of its paired users, except for relying on its own signal to noise ratio and t...

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

    International Nuclear Information System (INIS)

    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)

  11. Identifying and understanding barriers to sexually transmissible infection testing among young people

    OpenAIRE

    de Visser, Richard Oliver; O'Neill, Nancy

    2013-01-01

    Background: To counter the disproportionate impact of sexually transmissible infections (STIs) among young people and encourage higher levels of STI testing, it is necessary to identify the factors that influence STI testing. Methods: A mixed-methods study incorporating a cross-sectional quantitative survey and qualitative analysis of individual interviews was conducted in England. Some 275 university students aged 17-25 years completed an online questionnaire. Interviews were conduc...

  12. The native Wolbachia symbionts limit transmission of dengue virus in Aedes albopictus.

    Directory of Open Access Journals (Sweden)

    Laurence Mousson

    Full Text Available BACKGROUND: The chikungunya (CHIK outbreak that struck La Reunion Island in 2005 was preceded by few human cases of Dengue (DEN, but which surprisingly did not lead to an epidemic as might have been expected in a non-immune population. Both arboviral diseases are transmitted to humans by two main mosquito species, Aedes aegypti and Aedes albopictus. In the absence of the former, Ae. albopictus was the only species responsible for viral transmission on La Reunion Island. This mosquito is naturally super-infected with two Wolbachia strains, wAlbA and wAlbB. While Wolbachia does not affect replication of CHIK virus (CHIKV in Ae. albopictus, a similar effect was not observed with DEN virus (DENV. METHODS/PRINCIPAL FINDINGS: To understand the weak vectorial status of Ae. albopictus towards DENV, we used experimental oral infections of mosquitoes from La Reunion Island to characterize the impact of Wolbachia on DENV infection. Viral loads and Wolbachia densities were measured by quantitative PCR in different organs of Ae. albopictus where DENV replication takes place after ingestion. We found that: (i Wolbachia does not affect viral replication, (ii Wolbachia restricts viral density in salivary glands, and (iii Wolbachia limits transmission of DENV, as infectious viral particles were only detected in the saliva of Wolbachia-uninfected Ae. albopictus, 14 days after the infectious blood-meal. CONCLUSIONS: We show that Wolbachia does not affect the replication of DENV in Ae. albopictus. However, Wolbachia is able to reduce viral infection of salivary glands and limit transmission, suggesting a role of Wolbachia in naturally restricting the transmission of DENV in Ae. albopictus from La Reunion Island. The extension of this conclusion to other Ae. albopictus populations should be investigated.

  13. The limits and intensity of Plasmodium falciparum transmission: implications for malaria control and elimination worldwide.

    Directory of Open Access Journals (Sweden)

    Carlos A Guerra

    2008-02-01

    Full Text Available BACKGROUND: The efficient allocation of financial resources for malaria control using appropriate combinations of interventions requires accurate information on the geographic distribution of malaria risk. An evidence-based description of the global range of Plasmodium falciparum malaria and its endemicity has not been assembled in almost 40 y. This paper aims to define the global geographic distribution of P. falciparum malaria in 2007 and to provide a preliminary description of its transmission intensity within this range. METHODS AND FINDINGS: The global spatial distribution of P. falciparum malaria was generated using nationally reported case-incidence data, medical intelligence, and biological rules of transmission exclusion, using temperature and aridity limits informed by the bionomics of dominant Anopheles vector species. A total of 4,278 spatially unique cross-sectional survey estimates of P. falciparum parasite rates were assembled. Extractions from a population surface showed that 2.37 billion people lived in areas at any risk of P. falciparum transmission in 2007. Globally, almost 1 billion people lived under unstable, or extremely low, malaria risk. Almost all P. falciparum parasite rates above 50% were reported in Africa in a latitude band consistent with the distribution of Anopheles gambiae s.s. Conditions of low parasite prevalence were also common in Africa, however. Outside of Africa, P. falciparum malaria prevalence is largely hypoendemic (less than 10%, with the median below 5% in the areas surveyed. CONCLUSIONS: This new map is a plausible representation of the current extent of P. falciparum risk and the most contemporary summary of the population at risk of P. falciparum malaria within these limits. For 1 billion people at risk of unstable malaria transmission, elimination is epidemiologically feasible, and large areas of Africa are more amenable to control than appreciated previously. The release of this information in

  14. 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.

  15. Limits to foundation displacement of an extra high voltage transmission tower in a mining subsidence area

    Institute of Scientific and Technical Information of China (English)

    Shu Qianjin; Yuan Guanglin; Guo Guangli; Zhang Yunfei

    2012-01-01

    Given the background of a transmission tower erected on a particular mining subsidence area,we used finite element modeling to analyze the anti-deformation performance of transmission towers under a number of different load conditions,including horizontal foundation displacement,uneven vertical downward displacement,wind loads and icing conditions.The results show that the failure in stability of a single steel angle iron represents the limit of the tower given ground deformation.We calculated the corresponding limits of foundation displacements.The results indicate that compression displacement of the foundation is more dangerous than tension displacement.Under complex foundation displacement conditions,horizontal foundation displacement is a key factor leading to failure in the stability of towers.Under conditions of compression or tension displacement of the foundation,wind load becomes the key factor.Towers do not fail when foundation displacements are smaller than 1% (under tension) or 0.5% (under horizontal compression or single foundation subsidence) of the distance between two supports.

  16. Confocal soft X-ray scanning transmission microscopy: setup, alignment procedure and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Späth, Andreas [Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen (Germany); Raabe, Jörg [Paul Scherrer Institut, 5232 Villigen (Switzerland); Fink, Rainer H., E-mail: rainer.fink@fau.de [Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen (Germany); Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen (Germany)

    2015-01-01

    A conventional STXM setup has been upgraded with a second micro zone plate and aligned to confocal geometry. Two confocal geometries (in-line and off-axis) have been evaluated and a discussion on prospects and limitations is presented. Zone-plate-based scanning transmission soft X-ray microspectroscopy (STXM) is a well established technique for high-contrast imaging of sufficiently transparent specimens (e.g. ultrathin biological tissues, polymer materials, archaeometric specimens or magnetic thin films) with spatial resolutions in the regime of 20 nm and high spectroscopic or chemical sensitivity. However, due to the relatively large depth of focus of zone plates, the resolution of STXM along the optical axis so far stays unambiguously behind for thicker X-ray transparent specimens. This challenge can be addressed by the implementation of a second zone plate in the detection pathway of the beam, resulting in a confocal arrangement. Within this paper a first proof-of-principle study for a confocal STXM (cSTXM) and an elaborate alignment procedure in transmission and fluorescence geometry are presented. Based on first confocal soft X-ray micrographs of well known specimens, the advantage and limitation of cSTXM as well as further development potentials for future applications are discussed.

  17. The International Limits and Population at Risk of Plasmodium vivax Transmission in 2009

    Science.gov (United States)

    Guerra, Carlos A.; Howes, Rosalind E.; Patil, Anand P.; Gething, Peter W.; Van Boeckel, Thomas P.; Temperley, William H.; Kabaria, Caroline W.; Tatem, Andrew J.; Manh, Bui H.; Elyazar, Iqbal R. F.; Baird, J. Kevin; Snow, Robert W.; Hay, Simon I.

    2010-01-01

    development and control, P. vivax remains more widely distributed than P. falciparum and is a potential cause of morbidity and mortality amongst the 2.85 billion people living at risk of infection, the majority of whom are in the tropical belt of CSE Asia. The probability of infection is reduced massively across Africa by the frequency of the Duffy negative trait, but transmission does occur on the continent and is a concern for Duffy positive locals and travellers. The final map provides the spatial limits on which the endemicity of P. vivax transmission can be mapped to support future cartographic-based burden estimations. PMID:20689816

  18. Limited Area Coverage/High Resolution Picture Transmission (LAC/HRPT) data vegetative index calculation processor user's manual

    Science.gov (United States)

    Obrien, S. O. (Principal Investigator)

    1980-01-01

    The program, LACVIN, calculates vegetative indexes numbers on limited area coverage/high resolution picture transmission data for selected IJ grid sections. The IJ grid sections were previously extracted from the full resolution data tapes and stored on disk files.

  19. Limited BVDV transmission and full protection against CSFV transmission in pigs experimentally infected with BVDV type 1b

    NARCIS (Netherlands)

    Wieringa-Jelsma, H.; Quak, J.; Loeffen, W.L.A.

    2006-01-01

    Bovine viral diarrhea virus (BVDV) in pigs may interfere with the detection and epidemiology of classical swine fever virus (CSFV). To investigate the importance of BVDV infections in pigs, first we studied the transmission dynamics of a recent BVDV field isolate. Subsequently, the protection of BVD

  20. Confocal soft X-ray scanning transmission microscopy: setup, alignment procedure and limitations.

    Science.gov (United States)

    Späth, Andreas; Raabe, Jörg; Fink, Rainer H

    2015-01-01

    Zone-plate-based scanning transmission soft X-ray microspectroscopy (STXM) is a well established technique for high-contrast imaging of sufficiently transparent specimens (e.g. ultrathin biological tissues, polymer materials, archaeometric specimens or magnetic thin films) with spatial resolutions in the regime of 20 nm and high spectroscopic or chemical sensitivity. However, due to the relatively large depth of focus of zone plates, the resolution of STXM along the optical axis so far stays unambiguously behind for thicker X-ray transparent specimens. This challenge can be addressed by the implementation of a second zone plate in the detection pathway of the beam, resulting in a confocal arrangement. Within this paper a first proof-of-principle study for a confocal STXM (cSTXM) and an elaborate alignment procedure in transmission and fluorescence geometry are presented. Based on first confocal soft X-ray micrographs of well known specimens, the advantage and limitation of cSTXM as well as further development potentials for future applications are discussed.

  1. Limitations and barriers in access to care for male factor infertility.

    Science.gov (United States)

    Mehta, Akanksha; Nangia, Ajay K; Dupree, James M; Smith, James F

    2016-05-01

    The primary challenge to identifying and addressing barriers in access to care for male factor infertility is accurate measurement of the prevalence of male infertility. Current estimates are based on couples pursuing assisted reproduction, and likely underestimate the problem. These estimates also fail to account for the number of patients facing infertility due to cancer or cancer treatment. Lack of health insurance coverage for the diagnosis and treatment of infertility presents a major barrier for couples struggling with infertility. However, it is not the only barrier. Education level, household income, cultural norms, religious beliefs, geographic location, and the availability of specialty-trained reproductive urologists are all important factors in determining the ease with which patients access and obtain infertility care. Addressing each of these obstacles directly is imperative to improving reproductive care and outcomes for infertile couples in the United States. PMID:27054307

  2. Relationship of hepatitis B virus infection of placental barrier and hepatitis B virus intra-uterine transmission mechanism

    Institute of Scientific and Technical Information of China (English)

    Han Bai; Lin Zhang; Li Ma; Xiao-Guang Dou; Guo-He Feng; Gui-Zhen Zhao

    2007-01-01

    AIM: To explore the mechanism of intra-uterine transmission, the HBV infection status of placental tissue and in vitro cultured placental trophoblastic cells was tested through in vivo and in vitro experiments.METHODS: A variety of methods, such as ELISA, RTPCR, IHC staining and immunofluorescent staining were employed to test the HBV marker positive pregnant women's placenta and in vitro cultured placental trophoblastic cells.RESULTS: The HBV DNA levels in pregnant women's serum and fetal cord blood were correlated. For those cord blood samples positive for HBV DNA, their maternal blood levels of HBV DNA were at a high level. The HBsAg IHC staining positive cells could be seen in the placental tissues and the presence of HBV DNA detected. After coincubating the trophoblastic cells and HBV DNA positive serum in vitro, the expressions of both HBsAg and HBV DNA could be detected.CONCLUSION: The mechanism of HBV intra-uterine infection may be due to that HBV breaches the placental barrier and infects the fetus.

  3. Epimuscular myofascial force transmission between antagonistic and synergistic muscles can explain movement limitation in spastic paresis

    NARCIS (Netherlands)

    Huijing, Peter A.

    2007-01-01

    Details and concepts of intramuscular, extramuscular and intermuscular myofascial force transmission are reviewed. Some new experimental data are added regarding myofascial force transmission between antagonistic muscles across the interosseal membrane of the lower hind limb of the rat. Combined wit

  4. 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…

  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

    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. Nitrogen and phosphorus limitation in a coastal barrier salt marsh : the implications for vegetation succession

    NARCIS (Netherlands)

    van Wijnen, HJ; Bakker, JP

    1999-01-01

    1 A factorial fertilizer experiment was conducted in a 15-year-old coastal barrier salt marsh with a low soil nitrogen content, and in an older 100-year-old marsh with a higher nitrogen content. Plots were fertilized at high and low marsh elevations in both marshes. Nitrogen and phosphorus were appl

  7. Research of Efficiency of the Data Transmission Telecommunication Systems with Limited by the Frequency Stripe and Power

    OpenAIRE

    Gorbatyy, Ivan

    2010-01-01

    the efficiency of the data transmission telecommunication systems with limited by frequency stripe of telecommunication channel and signal power in channel with the use of modern kinds of signal modulation was explored. The results of efficiency of the systems at the concrete kinds of modulation were got. Recommendations in relation to application of definite kinds of modulation in the data transmission telecommunication systems were given.

  8. 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

    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

  9. Parametric Harmonic Generation as a Probe of Unconstrained Spin Magnetization Precession in the Shallow Barrier Limit.

    Science.gov (United States)

    Capua, Amir; Rettner, Charles; Parkin, Stuart S P

    2016-01-29

    We study the parametric excitation of high orders of magnetization precession in ultrathin films having perpendicular magnetic anisotropy. We observe that for a given driving field amplitude the harmonic generation can be increased by lowering the barrier with the application of an in-plane magnetic field in the manner of the Smit-Beljers effect. In this effect, the magnetic stiffness is reduced not by lowering the magnitude of the magnetic field upon which the spins precess, but rather by effectively releasing the field's "anchoring" point. This results in a shallow energy barrier where the electrons' spin is locally unconstrained. While the observation is unveiled in the form of nonlinear high harmonic generation, we believe that the physics whereby the barrier is suppressed by an external magnetic field may apply to other phenomena associated with ultrathin films. In these cases, such unconstrained motion may serve as a sensitive probe of the torques associated with proximate spin currents. Moreover, our approach may be used as a model system for the study of phase transitions in the field of nonlinear dynamics. PMID:26871356

  10. Structural and psycho-social limits to climate change adaptation in the great barrier reef region

    OpenAIRE

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

    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...

  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. 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

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

    Science.gov (United States)

    2012-12-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Essar Steel Minnesota, LLC v. Great Lakes Gas Transmission Limited... section 5 of the Natural Gas Act, 15 U.S.C. 717(a), Essar Steel Minnesota, LLC (Complainant) filed...

  15. 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.

  16. A Study on Guided and Unguided Transmission Medias and a Proposed Idea to Extend the Limit of Gi-Fi

    Directory of Open Access Journals (Sweden)

    Dr J Sebastian Nixon

    2016-07-01

    Full Text Available Networking in computers enables sharing of information by interconnecting the computing devices. The sharing of information is possible through transmission media. The transmission media is classified as wired or wireless. Wired media have limitation in geography. But wireless is not bounded by geography. In the wireless world the first wireless technology was infrared and it was a very slow technology. So, inventions were continued to find a better wireless technology, finally we got Bluetooth, Wi-Fi ,WI-MAX and Gi-Fi. In this paper we discussed about different Wired and Wireless Technologies and given a proposed idea to extend the limit of Gi-Fi beyond 10 meters

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

    Directory of Open Access Journals (Sweden)

    François-Denis Desgorces

    Full Text Available 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. 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.

  19. Characterizing the In-Phase Reflection Bandwidth Theoretical Limit of Artificial Magnetic Conductors With a Transmission Line Model

    Science.gov (United States)

    Xie, Yunsong; Fan, Xin; Chen, Yunpeng; Wilson, Jeefrey D.; Simons, Rainee N.; Xiao, John Q.

    2013-01-01

    We validate through simulation and experiment that artificial magnetic conductors (AMC s) can be well characterized by a transmission line model. The theoretical bandwidth limit of the in-phase reflection can be expressed in terms of the effective RLC parameters from the surface patch and the properties of the substrate. It is found that the existence of effective inductive components will reduce the in-phase reflection bandwidth of the AMC. Furthermore, we propose design strategies to optimize AMC structures with an in-phase reflection bandwidth closer to the theoretical limit.

  20. Limiting Power Transmission of Green Cellular Networks: Impact on Coverage and Capacity

    OpenAIRE

    Kélif, Jean-Marc; Coupechoux, Marceau; Marache, Frédéric

    2010-01-01

    Reducing power transmission is of primary importance in future green cellular networks. First of all, the induced reduction of the interference encourages the deployment of opportunistic radios in the same spectrum. Then, it directly implies a reduction of the energy consumption. At last, electric field radiations reduction mitigates the potential risks on health. From a technical point of view, power control is however likely to degrade network performance. In this paper, we evaluate the imp...

  1. Confocal soft X-ray scanning transmission microscopy: setup, alignment procedure and limitations

    OpenAIRE

    Späth, Andreas; Raabe, Jörg; Fink, Rainer H.

    2015-01-01

    Zone-plate-based scanning transmission soft X-ray microspectroscopy (STXM) is a well established technique for high-contrast imaging of sufficiently transparent specimens (e.g. ultrathin biological tissues, polymer materials, archaeometric specimens or magnetic thin films) with spatial resolutions in the regime of 20 nm and high spectroscopic or chemical sensitivity. However, due to the relatively large depth of focus of zone plates, the resolution of STXM along the optical axis so far stays ...

  2. Antecedent avian immunity limits tangential transmission of West Nile virus to humans.

    Directory of Open Access Journals (Sweden)

    Jennifer L Kwan

    Full Text Available BACKGROUND: West Nile virus (WNV is a mosquito-borne flavivirus maintained and amplified among birds and tangentially transmitted to humans and horses which may develop terminal neuroinvasive disease. Outbreaks typically have a three-year pattern of silent introduction, rapid amplification and subsidence, followed by intermittent recrudescence. Our hypothesis that amplification to outbreak levels is contingent upon antecedent seroprevalence within maintenance host populations was tested by tracking WNV transmission in Los Angeles, California from 2003 through 2011. METHODS: Prevalence of antibodies against WNV was monitored weekly in House Finches and House Sparrows. Tangential or spillover transmission was measured by seroconversions in sentinel chickens and by the number of West Nile neuroinvasive disease (WNND cases reported to the Los Angeles County Department of Public Health. RESULTS: Elevated seroprevalence in these avian populations was associated with the subsidence of outbreaks and in the antecedent dampening of amplification during succeeding years. Dilution of seroprevalence by recruitment resulted in the progressive loss of herd immunity following the 2004 outbreak, leading to recrudescence during 2008 and 2011. WNV appeared to be a significant cause of death in these avian species, because the survivorship of antibody positive birds significantly exceeded that of antibody negative birds. Cross-correlation analysis showed that seroprevalence was negatively correlated prior to the onset of human cases and then positively correlated, peaking at 4-6 weeks after the onset of tangential transmission. Antecedent seroprevalence during winter (Jan - Mar was negatively correlated with the number of WNND cases during the succeeding summer (Jul-Sep. CONCLUSIONS: Herd immunity levels within after hatching year avian maintenance host populations <10% during the antecedent late winter and spring period were followed on three occasions by

  3. Limitations and barriers for adopting sustainable management practices in different farm types across Europe

    Science.gov (United States)

    Guzmán, Gema; Portero, Ángela; Vanwalleghem, Tom; Pedrera, Ana; Jesús Gaitán, Antonio; Ten Berge, Hein

    2014-05-01

    Although apparently the conservation of natural resources such as water and soil does not represent important concerns for our society, the evolution of the world population and the degradation of these resources pose a challenge to improving agricultural food production capacity and conserving, and in some cases restoring, the environmental quality. Unfortunately, the history contains numerous examples of abandonment of these resources (McNeill 1992, Montgomery 2007). Although most of the agronomic conservation practices have been known for millennia, their implementation has often been hindered by non-agricultural motives (Davis et al. 2012). The European project CATCH-C (ten Berge 2011) started last year with the aim of evaluating sustainable soil management practices and exploring the difficulties for their adoption, both at farm and institutional level, to overcome them in the near future. As a first step with that purpose, a selection of best management practices (BMPs) based on interviews with advisors and scientific knowledge were proposed for each of the considered farm typologies: arable crops, permanent crops and pasture. These farm types are representative of the Mediterranean area in terms of agroecological properties, extension, economical importance and soil degradation problems. Semi-structured interviews were carried out by addressing different profiles of farmers to identify in a qualitative way the main limitations for adopting these BMPs on their farms. Different questionnaires were prepared based on the farmers' responses and launched at a larger scale, with the aim of achieving approximately 100 responses per each farm typology. Finally, responses from the questionnaires will be analyzed to explore the causes that hinder or impede the adoption of BMPs in different farm typologies. References: Davis A.S. et al. 2012. Plos ONE 7(10): e4719. doi:10.1371/journalpone.0047149. McNeill, J.R. 1992. The mountains of the Mediterranean world. Cambridge

  4. Health system barriers to implementation of collaborative TB and HIV activities including prevention of mother to child transmission in South Africa.

    Science.gov (United States)

    Uwimana, J; Jackson, D; Hausler, H; Zarowsky, C

    2012-05-01

    In South Africa, the control of TB and HIV co-infection remains a major challenge despite the availability of international and national guidelines for integration of TB and HIV services. This study was undertaken in KwaZulu-Natal, one of the provinces most affected by both TB and HIV, to identify and understand managers' and community care workers' (CCWs) perceptions of health systems barriers related to the implementation of collaborative TB/HIV activities, including prevention of mother to child transmission of HIV (PMTCT). We conducted 29 in-depth interviews with health managers at provincial, district and facility level and with managers of NGOs involved in TB and HIV care, as well as six focus group discussions with CCWs. Thematic analysis of transcripts revealed a convergence of perspectives on the process and the level of the implementation of policy directives on collaborative TB and HIV activities across all categories of respondents (i.e. province-, district-, facility- and community-based organizations). The majority of participants felt that the implementation of the policy was insufficiently consultative and that leadership and political will were lacking. The predominant themes related to health systems barriers include challenges related to structure and organisational culture; management, planning and power issues; unequal financing; and human resource capacity and regulatory problems notably relating to scope of practice of nurses and CCWs. Accelerated implementation of collaborative TB/HIV activities including PMTCT will require political will and leadership to address these health systems barriers. PMID:22394016

  5. THE LIMITING ABSORPTION METHOD FOR A TRANSMISSION PROBLEM IN ACOUSTIC SCATTERING

    Institute of Scientific and Technical Information of China (English)

    Messaoud SOUILAH

    2006-01-01

    The limiting absorption principle is used to solve the scattering problem of time harmonic acoustic waves by penetrable objects in Sobolev spaces. The method is based on integral representation of the solution using the Green's kernel of the Helmholtz equation.

  6. 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

  7. Dissemination and transmission of the E1-226V variant of chikungunya virus in Aedes albopictus are controlled at the midgut barrier level.

    Directory of Open Access Journals (Sweden)

    Camilo Arias-Goeta

    Full Text Available Emergence of arboviruses could result from their ability to exploit new environments, for example a new host. This ability is facilitated by the high mutation rate occurring during viral genome replication. The last emergence of chikungunya in the Indian Ocean region corroborates this statement since a single viral mutation at the position 226 on the E1 glycoprotein (E1-A226V was associated with enhanced transmission by the mosquito Aedes albopictus in regions where the major mosquito vector, Aedes aegypti, is absent.We used direct competition assays in vivo to dissect out the mechanisms underlying the selection of E1-226V by Ae. albopictus. When the original variant E1-226A and the newly emerged E1-226V were provided in the same blood-meal at equal titers to both species of mosquitoes, we found that the proportion of both variants was drastically different in the two mosquito species. Following ingestion of the infectious blood-meal, the E1-226V variant was preferentially selected in Ae. albopictus, whereas the E1-226A variant was sometimes favored in Ae. aegypti. Interestingly, when the two variants were introduced into the mosquitoes by intrathoracic inoculations, E1-226V was no longer favored for dissemination and transmission in Ae. albopictus, showing that the midgut barrier plays a key role in E1-226V selection.This study sheds light on the role of the midgut barrier in the selection of novel arbovirus emerging variants. We also bring new insight into how the pre-existing variant E1-226V was selected among other viral variants including E1-226A. Indeed the E1-226V variant present at low levels in natural viral populations could rapidly emerge after being selected in Ae. albopictus at the midgut barrier level.

  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. Mathematical limits of multilocus models: the genetic transmission of bipolar disorder.

    OpenAIRE

    Craddock, N; Khodel, V; Van Eerdewegh, P; Reich, T

    1995-01-01

    We describe a simple, graphical method for determining plausible modes of inheritance for complex traits and apply this to bipolar disorder. The constraints that allele frequencies and penetrances lie in the interval 0-1 impose limits on recurrence risks, KR, in relatives of an affected proband for a given population prevalence, KP. We have investigated these limits for KR in three classes of relatives (MZ co-twin, sibling, and parent/offspring) for the general single-locus model and for two ...

  10. Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting

    Energy Technology Data Exchange (ETDEWEB)

    De Backer, A.; Martinez, G.T. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); MacArthur, K.E.; Jones, L. [Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH (United Kingdom); Béché, A. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Nellist, P.D. [Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH (United Kingdom); Van Aert, S., E-mail: sandra.vanaert@uantwerpen.be [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2015-04-15

    Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. - Highlights: • Limited size and beam sensitivity of nano-particles challenge their quantification. • Keeping the electron dose to a minimum is therefore important. • Reliability of quantitative ADF STEM for atom-counting is demonstrated. • Limits for single atom sensitivity are discussed. • Limits are diagnosed by combining simulations and a statistical method.

  11. Effect of Large Scale Transmission Limitations on Renewable Energy Load Matching for Western U.S.: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Diakov, V.; Short, W.; Gilchrist, B.

    2012-06-01

    Based on the available geographically dispersed data for the Western U.S. (excluding Alaska), we analyze to what extent the geographic diversity of these resources can offset their variability. Without energy storage and assuming unlimited energy flows between regions, wind and PV can meet up to 80% of loads in Western U.S. while less than 10% of the generated power is curtailed. Limiting hourly energy flows by the aggregated transmission line carrying capacities decreases the fraction of the load that can be met with wind and PV generation to approximately 70%.

  12. 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.

  13. A limited participation model of the monetary transmission mechanism in the United Kingdom

    OpenAIRE

    Shamik Dhar; Stephen P Millard

    2000-01-01

    In this paper, a model of the UK economy is developed in which monetary growth determines inflation, but in which multiple shocks obscure the relationship between money and inflation. The model is a Dynamic Stochastic General Equilibrium model in which consumers can only participate in financial markets before shocks are observed; in other words, has the feature of 'limited participation'. The particular version of the model used in the paper is similar to other models of this class but with ...

  14. Blood-Brain Barrier and Breast Cancer Resistance Protein: A Limit to the Therapy of CNS Tumors and Neurodegenerative Diseases

    Science.gov (United States)

    Iorio, Anna Lisa; da Ros, Martina; Fantappiè, Ornella; Lucchesi, Maurizio; Facchini, Ludovica; Stival, Alessia; Becciani, Sabrina; Guidi, Milena; Favre, Claudio; de Martino, Maurizio; Genitori, Lorenzo; Sardi, Iacopo

    2016-01-01

    The treatment of brain tumors and neurodegenerative diseases, represents an ongoing challenge. In Central Nervous System (CNS) the achievement of therapeutic concentration of chemical agents is complicated by the presence of distinct set of efflux proteins, such as ATP-Binding Cassette (ABC) transporters localized on the Blood-Brain Barrier (BBB). The activity of ABC transporters seems to be a common mechanism that underlies the poor response of CNS diseases to therapies. The molecular characterization of Breast Cancer Resistance Protein (BCRP/ABCG2), as an ABC transporter conferring multidrug resistance (MDR), has stimulated many studies to investigate its activity on the BBB, its involvement in physiology and CNS diseases and its role in limiting the delivery of drugs in CNS. In this review, we highlight the activity and localization of BCRP on the BBB and the action that this efflux pump has on many conventional drugs or latest generation molecules used for the treatment of CNS tumors and other neurodegenerative diseases. PMID:26584727

  15. First experimental proof for aberration correction in XPEEM: Resolution, transmission enhancement, and limitation by space charge effects

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Th., E-mail: schmidtt@fhi-berlin.mpg.de [Fritz Haber Institute of the Max Planck Society, Department of Chemical Physics, Faradayweg 4-6, D-14195 Berlin (Germany); Sala, A.; Marchetto, H. [Fritz Haber Institute of the Max Planck Society, Department of Chemical Physics, Faradayweg 4-6, D-14195 Berlin (Germany); Umbach, E. [Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); Freund, H.-J. [Fritz Haber Institute of the Max Planck Society, Department of Chemical Physics, Faradayweg 4-6, D-14195 Berlin (Germany)

    2013-03-15

    The positive effect of double aberration correction in x-ray induced Photoelectron Emission Microscopy (XPEEM) has been successfully demonstrated for both, the lateral resolution and the transmission, using the Au 4f XPS peak for element specific imaging at a kinetic energy of 113 eV. The lateral resolution is improved by a factor of four, compared to a non-corrected system, whereas the transmission is enhanced by a factor of 5 at a moderate resolution of 80 nm. With an optimized system setting, a lateral resolution of 18 nm could be achieved, which is up to now the best value reported for energy filtered XPEEM imaging. However, the absolute resolution does not yet reach the theoretical limit of 2 nm, which is due to space charge limitation. This occurs along the entire optical axis up to the contrast aperture. In XPEEM the pulsed time structure of the exciting soft x-ray light source causes a short and highly intense electron pulse, which results in an image blurring. In contrast, the imaging with elastically reflected electrons in the low energy electron microscopy (LEEM) mode yields a resolution clearly below 5 nm. Technical solutions to reduce the space charge effect in an aberration-corrected spectro-microscope are discussed. - Highlights: ► First successful double aberration correction in XPEEM. ► Improvement of resolution and transmission by aberration correction. ► Lateral resolution of 18 nm in energy filtered XPEEM is the best up to now reported value. ► First investigation of space charge effects in aberrations corrected PEEM.

  16. Modelling transmission of vector-borne pathogens shows complex dynamics when vector feeding sites are limited.

    Directory of Open Access Journals (Sweden)

    Arik Kershenbaum

    Full Text Available The relationship between species richness and the prevalence of vector-borne disease has been widely studied with a range of outcomes. Increasing the number of host species for a pathogen may decrease infection prevalence (dilution effect, increase it (amplification, or have no effect. We derive a general model, and a specific implementation, which show that when the number of vector feeding sites on each host is limiting, the effects on pathogen dynamics of host population size are more complex than previously thought. The model examines vector-borne disease in the presence of different host species that are either competent or incompetent (i.e. that cannot transmit the pathogen to vectors as reservoirs for the pathogen. With a single host species present, the basic reproduction ratio R(0 is a non-monotonic function of the population size of host individuals (H, i.e. a value [Formula: see text] exists that maximises R(0. Surprisingly, if [Formula: see text] a reduction in host population size may actually increase R(0. Extending this model to a two-host species system, incompetent individuals from the second host species can alter the value of [Formula: see text] which may reverse the effect on pathogen prevalence of host population reduction. We argue that when vector-feeding sites on hosts are limiting, the net effect of increasing host diversity might not be correctly predicted using simple frequency-dependent epidemiological models.

  17. Mathematical limits of multilocus models: The genetic transmission of bipolar disorder

    Energy Technology Data Exchange (ETDEWEB)

    Craddock, N.; Khodel, V.; Van Eerdewegh, P.; Reich, T. [Washington Univ. School of Medicine, St. Louis, MO (United States)

    1995-09-01

    We describe a simple, graphical method for determining plausible modes of inheritance for complex traits and apply this to bipolar disorder. The constraints that allele frequencies and penetrances lie in the interval 0-1 impose limits on recurrence risks, K{sub R}, in relatives of an affected proband for a given population prevalence, K{sub p}. We have investigated these limits for K{sub R} in three classes of relatives (MZ co-twin, sibling, and parent/offspring) for the general single-locus model and for two types of multilocus models: heterogeneity and multiplicative. In our models we have assumed Hardy-Weinberg equilibrium, an all-or-none trait, absence of nongenetic resemblance between relatives, and negligible mutation at the disease loci. Although the true values of K{sub p} and the K{sub R}`s are only approximately known, observed population and family data for bipolar disorder are inconsistent with a single-locus model or with any heterogeneity model. In contrast, multiplicative models involving three or more loci are consistent with observed data and, thus, represent plausible models for the inheritance of bipolar disorder. Studies to determine the genetic basis of most bipolar disorder should use methods capable of detecting interacting oligogenes. 32 refs., 5 figs.

  18. 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…

  19. Piloting the promotion of bamboo skirt barriers to prevent Nipah virus transmission through date palm sap in Bangladesh.

    Science.gov (United States)

    Nahar, Nazmun; Mondal, Utpal Kumar; Hossain, M Jahangir; Khan, M Salah Uddin; Sultana, Rebeca; Gurley, Emily S; Luby, Stephen P

    2014-12-01

    Drinking raw date palm sap contaminated with infected fruit bat saliva or urine is an important mode of Nipah virus transmission to humans in Bangladesh. Bamboo skirts are an effective way to interrupt bat access to the sap. We conducted a study from November 2008 to March 2009 to explore the effectiveness of higher- and lower-intensity interventions by promoting bamboo skirt preparation and use among sap harvesters (gachhis). We spent 280 person-hours in two villages for the higher-intensity intervention and half that amount of time in two other villages for the lower-intensity intervention. To evaluate the interventions we followed up all gachhis once a month for three months. A high percentage of gachhis (83% in higher-, 65% in lower-intensity interventions) prepared and used a skirt of bamboo or other materials - jute stalk, dhoincha (Sesbania aculeata), or polythene - at least once after intervention. In general, 15% of gachhis consistently used skirts throughout the sap collection season. The intensive nature of this intervention is very expensive for a large-scale programme. Future efforts should focus on developing a low-cost behaviour change intervention and evaluate if it reduces the human exposure to potentially contaminated fresh date palm sap.

  20. Barriers to the implementation of programs for the prevention of mother-to-child transmission of HIV: A cross-sectional survey in rural and urban Uganda

    Directory of Open Access Journals (Sweden)

    Bajunirwe Francis

    2005-10-01

    Full Text Available Abstract Background Implementation of programs for the prevention of mother-to-child transmission (PMTCT of HIV faces a variety of barriers and challenges. The assessment of these challenges has generally been conducted in large urban health facilities. As programs expand into rural areas, the potential barriers that may be encountered there also need to be assessed. This study examines potential barriers that might affect the acceptability of interventions for PMTCT in rural and urban settings. Results Four hundred and four women at a large urban hospital and three rural clinics that had recently started implementing PMTCT were interviewed. Level of knowledge of MTCT and preference for rapid HIV testing were equally high in both areas, but rural women had a higher tendency to think that they should consult their husbands before testing, with borderline statistical significance (72% vs. 64% p = 0.09. Health facility-based deliveries were significantly lower among mothers in rural areas compared to those in the urban setting. Overall, significant predictors of willingness to test for HIV were post-primary education (OR = 3.1 95% CI 1.2, 7.7 and knowledge about rapid HIV tests (OR = 1.8, 95% CI 1.01, 3.4. The strongest predictor of willingness to accept an HIV test was the woman's perception that her husband would approve of her testing for HIV. Women who thought their husbands would approve were almost six times more likely to report a willingness to be tested compared to those who thought their husbands would not approve (OR = 5.6, 95% CI 2.8, 11.2. Conclusion Lessons learned in large urban hospitals can be generalized to rural facilities, but the lower proportion of facility-based deliveries in rural areas needs to be addressed. Same-day results are likely to ensure high uptake of HIV testing services but male spousal involvement should be considered, particularly for rural areas. Universal Primary Education will support the success of PMTCT

  1. The capacity limitations of power transmission cable lines in the structure of civil and industry engineering networks

    Directory of Open Access Journals (Sweden)

    V.V. Titkov

    2014-10-01

    Full Text Available The present study analyses heat modes of high voltage cable lines typical for laying in the area of communications, different obstacles and engineering networks, such as, for instance, hot water supply lines. It is well-known that the load capacity of modern high voltage cable lines with a plastic insulation is limited by the maximum permissible heating temperature of 90 °C. This study focuses on two typical cases of heating mains influence on heat exchange of a power cable line with surrounding ground: 1 the rapprochement of a power cable line with a heating main – the segment of a parallel disposal of a cable line and a heating pipe; 2 the intersection of a cable line and a heating main – the area where the cable line going above the heating main crosses it at the angle of 90 degrees. We have proposed the model of a prolonged cylinder with inhomogeneous thermophysical and heat exchange parameters distribution along this cable for the temperature distribution along a power cable in terms of non-regular laying. The finite-element method has been used to solve the problem of cable line heating fields near heating main calculation. A quantitative analysis of the cases described above has revealed that the local cable temperature excess up to several tenths of degrees is typical for them. It leads to the transmission capacity decrease by 20–30 % and limits the cable line ability to cover peak loads occurring in industrial, natural or other disasters. Besides, cable line segment spillover out of permissible temperature mode leads to emergency, power shortage and further repairing efforts. While engineering and calculations of the cable lines modes, our proposed techniques allow avoiding critical temperature conditions which may lead to the consequences described above.

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    Christoforos Mallouris

    2012-07-01

    Full Text Available Introduction: 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. Discussion: 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. Conclusions: 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

  4. 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.

  5. Large barrier, highly uniform and reproducible Ni-Si/4H-SiC forward Schottky diode characteristics: testing the limits of Tung's model

    International Nuclear Information System (INIS)

    We report highly ideal (n 14–1016 cm−3, apart from a slight decrease consistent with image force lowering. This remarkable uniformity was achieved by careful optimization of the annealing of the Schottky interface to minimize non-idealities that could lead to inhomogeneity. Tung's barrier inhomogeneity model was used to quantify the level of inhomogeneity in the optimized annealed diodes. The estimated ‘bulk’ barrier height (1.75 eV) was consistent with the Shockley–Mott limit for the Ni–Si/4H-SiC interface, implying an unpinned Fermi level. But the model was not useful to explain the poor ideality in unoptimized, as-deposited Schottky contacts (n = 1.6 − 2.5). We show analytically and numerically that only idealities n < 1.21 can be explained using Tung's model, irrespective of material system, indicating that the barrier height inhomogeneity is not the only cause of poor ideality in Schottky diodes. For explaining this highly non-ideal behaviour, other factors (e.g. interface traps, morphological defects, extrinsic impurities, etc) need to be considered. (paper)

  6. Organizational Barriers Limiting Women’s Participation in Women-In-Agriculture (Wia Programme in Umuahia Agricultural Zone of Abia State, Nigeria

    Directory of Open Access Journals (Sweden)

    G.E. Ifenkwe

    2012-08-01

    Full Text Available Development literature is replete with evidence of high level of involvement of women in agricultural production and value addition activities in Nigeria. This paper highlights organizational barriers limiting women’s participation in Women-in-Agriculture (WIA program, one of the women’s enabling agricultural program in Abia State, Nigeria. Multi-stage random sampling technique was adopted in selecting one hundred and twenty women farmers studied. Simple statistical tools (frequencies and percentages were used in data analysis. The results show that agency-related and organizational problems accounted for over 80% of the constraints limiting participation in the program. They also differ significantly from client or farmer-related problems. Considering the huge financial investments in the agricultural sector, and the Federal Government’s policy thrust on food security, the paper recommends involvement of all stakeholders who must contribute their quota towards sustainable food security in Nigeria.

  7. 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.

  8. Simulations on Asymmetric Three-barrier Transmission Coefficients under Different Bias and Temperatures%不同偏压温度下非对称三势垒透射系数的模拟计算

    Institute of Scientific and Technical Information of China (English)

    赵瑞娟; 安盼龙; 许丽萍; 杨艳

    2012-01-01

    非对称多势垒可获得比双势垒更大的共振隧穿电流及更良好的峰谷比。通过分析单电子对任意势垒透射的理论模型,建立了任意非对称三势垒模型,研究了不同偏压和温度对透射系数的影响,并得出结论,为进一步设计非对称量子器件提供理论指导。%Asymmetric multi-barrier can obtain larger resonant tunneling current and better peak-valley ratio than double barrier. By analyzing the theoretical models of single-electron transmission on any harrier, an arbitrary asymmetric three-barrier model was established. Effects of different bias and temperatures on the transmission coefficient were studied. It provides a theoretical guidance for the further design of asymmetric quantum devices.

  9. Spectrum Sharing between Cooperative Relay and Ad-hoc Networks: Dynamic Transmissions under Computation and Signaling Limitations

    CERN Document Server

    Sun, Yin; Li, Yunzhou; Zhou, Shidong; Xu, Xibin

    2010-01-01

    This paper studies a spectrum sharing scenario between an uplink cognitive relay network (CRN) and some nearby low power ad-hoc networks. In particular, the dynamic resource allocation of the CRN is analyzed, which aims to minimize the average interfering time with the ad-hoc networks subject to a minimal average uplink throughput constraint. A long term average rate formula is considered, which is achieved by a half-duplex decode-and-forward (DF) relay strategy with multi-channel transmissions. Both the source and relay are allowed to queue their data, by which they can adjust the transmission rates flexibly based on sensing and predicting the channel state and ad-hoc traffic. The dynamic resource allocation of the CRN is formulated as a non-convex stochastic optimization problem. By carefully analyzing the optimal transmission time scheduling, it is reduced to a stochastic convex optimization problem and solved by the dual optimization method. The signaling and computation processes are designed carefully t...

  10. Rates, barriers and outcomes of HIV serostatus disclosure among women in developing countries: implications for prevention of mother-to-child transmission programmes.

    OpenAIRE

    Medley, Amy; Garcia-Moreno, Claudia; McGill, Scott; Maman, Suzanne

    2004-01-01

    This paper synthesizes the rates, barriers, and outcomes of HIV serostatus disclosure among women in developing countries. We identified 17 studies from peer-reviewed journals and international conference abstracts--15 from sub-Saharan Africa and 2 from south-east Asia--that included information on either the rates, barriers or outcomes of HIV serostatus disclosure among women in developing countries. The rates of disclosure reported in these studies ranged from 16.7% to 86%, with women atten...

  11. Transmission electron microscopy study for investigating high-temperature reliability of Ti{sub 10}W{sub 90}-based and Ta-based diffusion barriers up to 600 C

    Energy Technology Data Exchange (ETDEWEB)

    Budhiman, Nando; Schuermann, Ulrich; Kienle, Lorenz [Institute of Material Science, Christian-Albrechts-Universitaet, Kiel (Germany); Jensen, Bjoern [Fraunhofer Institute for Silicon Technology, Itzehoe (Germany); Chemnitz, Steffen; Wagner, Bernhard [Institute of Material Science, Christian-Albrechts-Universitaet, Kiel (Germany); Fraunhofer Institute for Silicon Technology, Itzehoe (Germany)

    2016-04-15

    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{sub 10}W{sub 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{sub 10}W{sub 90} layers, and between Ni and adjoining Ta layers in the Ti{sub 10}W{sub 90}-based and Ta-based barriers, respectively, are observed due to annealing. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. 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

  13. 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.

  14. Stochastic limits in synchronous imaging of sub-micron magnetization dynamics using scanning transmission x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cheng C.; Kaznatcheev K.; Bailey, W.E.

    2012-02-28

    We demonstrate a synchronous (lock-in) technique for imaging thin-film magnetization dynamics using scanning transmission x-ray microscopy (STXM). Gated photon counting synchronized with magnetic field modulation allows image acquisition with differential contrast for high and low magnetization. We have applied this technique to 5 x 12 {micro}m{sup 2} Ni{sub 81}Fe{sub 19} ellipses with well-defined closure domains at remanence. The stochastic nature of the domain wall motion and nucleation is apparent in images recorded during cycling along successive major hysteresis loops. Synchronous imaging shows the clearest enhancement of contrast for small-amplitude domain wall motion, with a less obvious benefit at higher fields/displacements. The technique shows promise for the contrast enhancement of magnetization in dynamics in STXM.

  15. 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

    Science.gov (United States)

    Kuete, Martin; Yuan, HongFang; Tchoua Kemayou, Aude Laure; Songo, Emmanuel Ancel; Yang, Fan; Ma, XiuLan; Xiong, ChengLiang; Zhang, HuiPing

    2016-01-01

    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 abortions, 65% had tried to avoid the current pregnancy, and 12% of women were ART naïve. Several predictors such as education, abortion rate, unplanned pregnancies, and partners’ decision were associated with the nonuse of effective contraceptive methods. Moreover, barriers including sex inequity, lack of partner support, ART shortages, and lack of HIV viral load monitoring were prevalent among the participants (P=0.001). However FPS use, ART compliance, and safe options to PMTCT

  16. Extremal surface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Netta; Wall, Aron C. [Department of Physics, University of California,Santa Barbara, CA 93106 (United States)

    2014-03-13

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy.

  17. Limited potential for mosquito transmission of genetically engineered, live-attenuated western equine encephalitis virus vaccine candidates.

    Science.gov (United States)

    Turell, Michael J; O'Guinn, Monica L; Parker, Michael D

    2003-02-01

    Specific mutations associated with attenuation of Venezuelan equine encephalitis (VEE) virus in rodent models were identified during efforts to develop an improved VEE vaccine. Analogous mutations were produced in full-length cDNA clones of the Cba 87 strain of western equine encephalitis (WEE) virus by site-directed mutagenesis in an attempt to develop an improved WEE vaccine. Isogenic viral strains with these mutations were recovered after transfection of baby hamster kidney cells with infectious RNA. We evaluated two of these strains (WE2102 and WE2130) for their ability to replicate in and be transmitted by Culex tarsalis, the principal natural vector of WEE virus in the United States. Each of the vaccine candidates contained a deletion of the PE2 furin cleavage site and a secondary mutation in the E1 or E2 glycoprotein. Both of these potential candidates replicated in mosquitoes significantly less efficiently than did either wild-type WEE (Cba 87) virus or the parental clone (WE2000). Likewise, after intrathoracic inoculation, mosquitoes transmitted the vaccine candidate strains significantly less efficiently than they transmitted either the wild-type or the parental clone. One-day-old chickens vaccinated with either of the two vaccine candidates did not become viremic when challenged with virulent WEE virus two weeks later. Mutations that result in less efficient replication in or transmission by mosquitoes should enhance vaccine safety and reduce the possibility of accidental introduction of the vaccine strain to unintentional hosts.

  18. 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.

  19. The influence of interfacial growth patterns on the transmission properties of carriers through nonabrupt GaAs/Al xGa 1- xAs single barriers

    Science.gov (United States)

    Lima, M. C. A.; Junior, J. M. Pereira; Farias, G. A.; Freire, V. N.

    1995-06-01

    The influence of interfacial growth patterns on the tunelling of carriers through nonabrupt GaAs/Al xCa 1- xAs single barriers is studied. Five interfacial growth patterns are considered, all of them representative of interfacial alloy variations generated by different growth techniques. With a generalization of the scheme proposed previously by Freire et al [Superlatt. Microstruct. 1, 17 (1992)], the inter-related single barrier potential and effective mass is obtained. The envelope function equation with a position dependent kinetic energy operator is solved with a multistep scheme. The position of the resonant peaks, their peak-to-valley ratios, and the mean width of the resonance structures are shown to depend on the interfacial growth patterns.

  20. A Limiting Current Oxygen Sensor Based on LSGM as a Solid Electrolyte and LSGMN ( N = Fe, Co) as a Dense Diffusion Barrier

    Science.gov (United States)

    Liu, Tao; Gao, Xiang; He, Bei-Gang; Yu, Jing-Kun

    2016-07-01

    The La0.8Sr0.2(Ga1- x Co x )0.8Mg0.2O3- δ (LSGMC x = 0.05, 0.1, 0.15, 0.2, 0.25) and La0.8Sr0.2(Ga1- x Fe x )0.8Mg0.2O3- δ (LSGMF x = 0.1, 0.2, 0.3) samples were prepared by solid-state reaction. The structure, conductivity, thermal expansion behavior, and chemical compatibility were studied by XRD, dilatometry, and four-terminal method. A limiting current oxygen sensor was prepared with La0.8Sr0.2Ga0.83Mg0.17O2.815 as a solid electrolyte and La0.8Sr0.2(Ga0.75Co0.25)0.8Mg0.2O3- δ as a dense diffusion barrier. The oxygen-sensitive characteristic was measured at different oxygen concentrations. The results show that the phase structure of samples is cubic, except La0.8Sr0.2(Ga0.75Co0.25)0.8Mg0.2O3- δ , which has a hexagonal structure. The change in activation energy for electrical conductivity and the increase in thermal expansion coefficient are confirmed to correlate with an increasing concentration of oxygen vacancies. The limiting current oxygen sensor exhibits a good limiting current platform and the limiting current depends linearly on the oxygen concentration: I L(mA) = 12.8519 + 2.2667 x_{{{O}_{{2}} }} (mol%, 0 < x_{{{{O}}_{ 2} }} < 3.31) at 750 °C, I L(mA) = 14.3222 + 3.5180 x_{{{O}_{{2}} }} (mol%, 0 < x_{{{{O}}_{ 2} }} < 4.16) at 800 °C, and I L(mA) = 15.2872 + 5.0269x_{{{O}_{{2}} }}(mol%, 0 < x_{{{{O}}_{ 2} }} < 4.12) at 850 °C. The sensor has the best sensitivity at 850 °C. As the oxygen concentration increases, the interface resistance of the sensor decreases at 850 °C.

  1. Multilayer moisture barrier

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Market Based Criteria for Congestion Management and Transmission Pricing

    Directory of Open Access Journals (Sweden)

    Miss. Archana Jaisisngpure

    2014-07-01

    Full Text Available -Congestion Management is one of the major tasks performed by system operator to ensure the operation of transmission system within operating limits. In the emerging electric power market, the congestion management becomes extremely important and it can impose a barrier to the electricity trading. In the present paper, a concept of transmission congestion penalty factors is developed and implemented to control power overflows in transmission lines for congestion management. Here we presents a Re-dispatch methodology for cost of transmission network to its user. The transmission price computation considers the physical impact caused by the market agents in the transmission network. The paper includes case study for IEEE 5 bus power system.

  3. Separation of parent homopolymers from polystyrene and poly(ethylene oxide) based block copolymers by liquid chromatography under limiting conditions of desorption-3. Study of barrier efficiency according to block copolymers' chemical composition.

    Science.gov (United States)

    Rollet, Marion; Pelletier, Bérengère; Berek, Dušan; Maria, Sébastien; Phan, Trang N T; Gigmes, Didier

    2016-09-01

    Liquid Chromatography under Limiting Conditions of Desorption (LC LCD) is a powerful separation tool for multicomponent polymer systems. This technique is based on a barrier effect of an appropriate solvent, which is injected in front of the sample, and which decelerates the elution of selected macromolecules. In this study, the barrier effects have been evaluated for triblock copolymers polystyrene-b-poly(ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) according to the content of polystyrene (wt% PS) and PEO-block molar mass. PS-b-PEO-b-PS samples were prepared by Atom Transfer Radical Polymerization (ATRP). The presence of respective parent homopolymers was investigated by applying optimized LC LCD conditions. It was found that the barrier composition largely affects the efficiency of separation and it ought to be adjusted for particular composition range of block copolymers.

  4. Barriers to radiant barriers

    Energy Technology Data Exchange (ETDEWEB)

    Henke, C.

    Radiant barriers are an energy saving device which decrease the heat lost through radiant heat transfer. The primary reason to install it is to save on air conditioning costs, as it prevents the loss of heat through the attic. They have been the subject of much controversy, as the claims made by many manufacturers were extreme (up to 100% heat shielding), with the consumer paying high prices for ineffective devices. The authors outline criteria for the consumer to consider when buying radiant warmers and then give installation tips for both new constructions and retrofits.

  5. 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…

  6. Transmission line model for nanoelectronics

    OpenAIRE

    Nelin E. A.

    2009-01-01

    Analytical expressions for resonant parametres and characteristics of typical barrier nanoelectronic structures have been received on the basis of the transmission line model. Characteristics illustrating the efficiency of such approach are presented in the article.

  7. Transmission line model for nanoelectronics

    Directory of Open Access Journals (Sweden)

    Nelin E. A.

    2009-08-01

    Full Text Available Analytical expressions for resonant parametres and characteristics of typical barrier nanoelectronic structures have been received on the basis of the transmission line model. Characteristics illustrating the efficiency of such approach are presented in the article.

  8. A continuum limit for the Kronig-Penney model

    Science.gov (United States)

    Colangeli, Matteo; Ndreca, Sokol; Procacci, Aldo

    2015-06-01

    We investigate the transmission properties of a quantum one-dimensional periodic system of fixed length L, with N barriers of constant height V and width λ and N wells of width δ. In particular, we study the behaviour of the transmission coefficient in the limit N → ∞, with L fixed. This is achieved by letting δ and λ both scale as 1/N, in such a way that their ratio γ = λ/δ is a fixed parameter characterizing the model. In this continuum limit, the multi-barrier system behaves as it were constituted by a unique barrier of constant height Eo = (γV)/(1 + γ). The analysis of the dispersion relation of the model shows the presence of forbidden energy bands at any finite N.

  9. Barrier function in the ocular surface: from conventional paradigms to new opportunities.

    Science.gov (United States)

    Leong, Yuan-Yuh; Tong, Louis

    2015-04-01

    By providing a physical and immunological barrier, the ocular surface serves the important function of protecting the vision apparatus. The barrier function keeps the cornea relatively dehydrated, preserving transparency for transmission of light. In many instances, dysfunction of this barrier leads to clinical diseases, such as dry eye, infectious keratitis, allergic keratoconjunctivitis, chemical injury, and persistent epithelial defects. Herein, we review the components of the epithelial barrier in the ocular surface, i.e., the transcellular and paracellular pathways, and describe the methodologies for measuring barrier function in vitro, in animals, and in clinical studies. The usefulness and limitations of these techniques are discussed. Recent studies in the regulation of individual tight junction proteins, the occludins, the zonula occludens, and the claudins, are also reviewed. Several potential interventional strategies based on the knowledge gained from these studies are noted. PMID:25881994

  10. TLR2 signaling decreases transmission of Streptococcus pneumoniae by limiting bacterial shedding in an infant mouse Influenza A co-infection model.

    Directory of Open Access Journals (Sweden)

    Aimee L Richard

    2014-08-01

    Full Text Available While the importance of transmission of pathogens is widely accepted, there is currently little mechanistic understanding of this process. Nasal carriage of Streptococcus pneumoniae (the pneumococcus is common in humans, especially in early childhood, and is a prerequisite for the development of disease and transmission among hosts. In this study, we adapted an infant mouse model to elucidate host determinants of transmission of S. pneumoniae from inoculated index mice to uninfected contact mice. In the context of co-infection with influenza A virus, the pneumococcus was transmitted among wildtype littermates, with approximately half of the contact mice acquiring colonization. Mice deficient for TLR2 were colonized to a similar density but transmitted S. pneumoniae more efficiently (100% transmission than wildtype animals and showed decreased expression of interferon α and higher viral titers. The greater viral burden in tlr2-/- mice correlated with heightened inflammation, and was responsible for an increase in bacterial shedding from the mouse nose. The role of TLR2 signaling was confirmed by intranasal treatment of wildtype mice with the agonist Pam3Cys, which decreased inflammation and reduced bacterial shedding and transmission. Taken together, these results suggest that the innate immune response to influenza virus promotes bacterial shedding, allowing the bacteria to transit from host to host. These findings provide insight into the role of host factors in the increased pneumococcal carriage rates seen during flu season and contribute to our overall understanding of pathogen transmission.

  11. Wave packet propagation across barriers by semiclassical initial value methods

    Science.gov (United States)

    Petersen, Jakob; Kay, Kenneth G.

    2015-07-01

    Semiclassical initial value representation (IVR) formulas for the propagator have difficulty describing tunneling through barriers. A key reason is that these formulas do not automatically reduce, in the classical limit, to the version of the Van Vleck-Gutzwiller (VVG) propagator required to treat barrier tunneling, which involves trajectories that have complex initial conditions and that follow paths in complex time. In this work, a simple IVR expression, that has the correct tunneling form in the classical limit, is derived for the propagator in the case of one-dimensional barrier transmission. Similarly, an IVR formula, that reduces to the Generalized Gaussian Wave Packet Dynamics (GGWPD) expression [D. Huber, E. J. Heller, and R. Littlejohn, J. Chem. Phys. 89, 2003 (1988)] in the classical limit, is derived for the transmitted wave packet. Uniform semiclassical versions of the IVR formulas are presented and simplified expressions in terms of real trajectories and WKB penetration factors are described. Numerical tests show that the uniform IVR treatment gives good results for wave packet transmission through the Eckart and Gaussian barriers in all cases examined. In contrast, even when applied with the proper complex trajectories, the VVG and GGWPD treatments are inaccurate when the mean energy of the wave packet is near the classical transmission threshold. The IVR expressions for the propagator and wave packet are cast as contour integrals in the complex space of initial conditions and these are generalized to potentially allow treatment of a larger variety of systems. A steepest descent analysis of the contour integral formula for the wave packet in the present cases confirms its relationship to the GGWPD method, verifies its semiclassical validity, and explains results of numerical calculations.

  12. Underground explosion barriers - a review

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, B.; O`Beirne, T. [ACIRL Ltd., Booval, Qld. (Australia)

    1997-12-31

    The paper focuses on explosibility conditions in underground coal mines, the behaviour of explosions from initiating gas ignition to violent dust explosions and the effectiveness and limits of operation of current designs of passive explosion barriers in suppressing the flame front. The paper also discusses performance evaluations made in full scale explosion galleries and the use of alternatives to passive barriers, including the installation of active barriers under some circumstances.

  13. Klein tunneling through an oblique barrier in graphene ribbons

    CERN Document Server

    Oh, J H

    2010-01-01

    We study a transmission coefficient of graphene nanoribbons with a top gate which acts as an oblique barrier. Using a Green function method based on the Dirac-like equation, scattering among transverse modes due to the oblique barrier is taken into account numerically. In contrast to the 2-dimensional graphene sheet, we find that the pattern of transmission in graphene ribbons depends strongly on the electronic structure in the region of the barrier. Consequently, irregular structures in the transmission coefficient are predicted while perfect transmission is still calculated in the case of metallic graphene independently of angle and length of the oblique barrier.

  14. Barriers to Physical Activity Among Gay Men.

    Science.gov (United States)

    Cary, Miranda A; Brittain, Danielle R; Dinger, Mary K; Ford, Melissa L; Cain, Meagan; Sharp, Teresa A

    2016-09-01

    Gay men may not be physically active at recommended levels to achieve health benefits. Thus, a need exists to identify general (i.e., common across populations) and population-specific barriers that hinder or stop gay men from participating in physical activity (PA). Salient barriers may be identified through the extent each barrier limits PA (i.e., barrier limitation) and the level of one's confidence to overcome barriers and engage in PA (i.e., self-regulatory efficacy). The purposes of this study were to (1) provide a description of general and population-specific barriers to PA among sufficiently and insufficiently active gay men, (2) identify barrier limitation and self-regulatory efficacy for the reported barriers, and (3) examine the associations between meeting the current PA recommendation, barrier limitation, and self-regulatory efficacy. Participants were 108 self-identified gay males aged 21 to 64 years who completed a web-based survey. A total of 35 general barriers and no population-specific barriers were identified by the sufficiently and insufficiently active groups. The sufficiently active group reported higher self-regulatory efficacy and lower barrier limitation for nearly all reported barriers. A binary logistic regression used to examine the associations between PA, barrier limitation, and self-regulatory efficacy was statistically significant, χ(2)(2, N = 108) = 19.26, p < .0001, R(2) = .16. Only barrier limitation significantly contributed to the model. Future research should continue to examine barriers to PA among gay men to determine whether an intervention needs to be designed specifically for gay men or whether a one-size-fits-all intervention would be effective in helping all men overcome common barriers to engaging in PA. PMID:25643585

  15. Part I: Minicircle vector technology limits DNA size restrictions on ex vivo gene delivery using nanoparticle vectors: Overcoming a translational barrier in neural stem cell therapy.

    Science.gov (United States)

    Fernandes, Alinda R; Chari, Divya M

    2016-09-28

    Genetically engineered neural stem cell (NSC) transplant populations offer key benefits in regenerative neurology, for release of therapeutic biomolecules in ex vivo gene therapy. NSCs are 'hard-to-transfect' but amenable to 'magnetofection'. Despite the high clinical potential of this approach, the low and transient transfection associated with the large size of therapeutic DNA constructs is a critical barrier to translation. We demonstrate for the first time that DNA minicircles (small DNA vectors encoding essential gene expression components but devoid of a bacterial backbone, thereby reducing construct size versus conventional plasmids) deployed with magnetofection achieve the highest, safe non-viral DNA transfection levels (up to 54%) reported so far for primary NSCs. Minicircle-functionalized magnetic nanoparticle (MNP)-mediated gene delivery also resulted in sustained gene expression for up to four weeks. All daughter cell types of engineered NSCs (neurons, astrocytes and oligodendrocytes) were transfected (in contrast to conventional plasmids which usually yield transfected astrocytes only), offering advantages for targeted cell engineering. In addition to enhancing MNP functionality as gene delivery vectors, minicircle technology provides key benefits from safety/scale up perspectives. Therefore, we consider the proof-of-concept of fusion of technologies used here offers high potential as a clinically translatable genetic modification strategy for cell therapy.

  16. Transport Properties for Triangular Barriers in Graphene

    OpenAIRE

    Mouhafid, Abderrahim El; Jellal, Ahmed

    2013-01-01

    We theoretically study the electronic transport properties of Dirac fermions through one and double triangular barriers in graphene. Using the transfer matrix method, we determine the transmission, conductance and Fano factor. They are obtained to be various parameters dependent such as well width, barrier height and barrier width. Therefore, different discussions are given and comparison with the previous significant works is done. In particular, it is shown that at Dirac point the Dirac fer...

  17. Supplemental Release Limits for the Directed Reuse of Steel in Road Barriers and Lead in Shielding Products by the Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, RL

    2006-04-07

    The DOE National Center of Excellence for Metals Recycle (NMR) proposes to define and implement a complex-wide directed reuse strategy for surplus radiologically impacted lead (Pb) and steel as part of the U.S. Department of Energy's commitment to the safe and cost-effective recycle or reuse of excess materials and equipment across the DOE complex. NMR will, under this proposal, act on behalf of the DOE Office of Environmental Management, Office of Technical Program Integration (specifically EM-22), as the Department's clearinghouse for DOE surplus lead, steel and products created from these materials by developing and maintaining a cost-effective commercially-based contaminated lead and steel recycle program. It is NMR's intention, through this directed reuse strategy, to mitigate the adverse environmental and economic consequences of managing surplus lead and steel as a waste within the complex. This approach promotes the safe and cost-effective reuse of scrap metals in support of the Department's goals of resource utilization, energy conservation, pollution prevention and waste minimization. This report discusses recommendations for supplemental radiological release limits for the directed reuse of contaminated lead and steel by the DOE within the nuclear industry. The limits were originally selected from the American National Standards Institute and Health Physics Society standard N13.12 titled ''Surface and Volume Radioactivity Standards for Clearance'' (Health Physics Society, 1999) but were subsequently modified as a result of application-specific issues. Both the health and measurement implications from the adoption and use of the limits for directed reuse scenarios are discussed within this report.

  18. Impacts from Deployment Barriers on the United States Wind Power Industry: Overview & Preliminary Findings (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, E.; Tegen, S.; Hand, M.; Heimiller, D.

    2012-09-01

    Regardless of cost and performance some wind projects are unable to proceed to commissioning as a result of deployment barriers. Principal deployment barriers in the industry today include: wildlife, public acceptance, access to transmission, and radar. To date, methods for understanding these non-technical barriers have failed to accurately characterize the costs imposed by deployment barriers and the degree of impact to the industry. Analytical challenges include limited data and modeling capabilities. Changes in policy and regulation, among other factors, also add complexity to analysis of impacts from deployment barriers. This presentation details preliminary results from new NREL analysis focused on quantifying the impact of deployment barriers on the wind resource of the United States, the installed cost of wind projects, and the total electric power system cost of a 20% wind energy future. In terms of impacts to wind project costs and developable land, preliminary findings suggest that deployment barriers are secondary to market drivers such as demand. Nevertheless, impacts to wind project costs are on the order of $100/kW and a substantial share of the potentially developable windy land in the United States is indeed affected by deployment barriers.

  19. 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

    2014-05-01

    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. PMID:24921795

  20. A temperature-limited assessment of the risk of Rift Valley fever transmission and establishment in the continental United States of America

    Directory of Open Access Journals (Sweden)

    Sarah K. Konrad

    2012-05-01

    Full Text Available The rapid spread of West Nile virus across North America after its introduction in 1999 highlights the potential for foreign arboviruses to become established in the United States of America. Of particular concern is Rift Valley fever virus (RVFV, which has been responsible for multiple African epidemics resulting in death of both humans and livestock, as well as major economic disruption due to livestock loss and trade restrictions. Modern globalization, travel, and commerce allow viruses to easily jump from one continent to another; and it is likely only a matter of time before RVFV reaches North American shores. We used a degree-day model in combination with livestock population data and a pathways analysis to identify regions and times where RVFV is most likely to enter and become established in the United States of America. Transmission risk of the disease varies across the country from 325 annual risk days in parts of Florida to zero risk days in the far North and in high mountain regions. Areas of particular concern are where there are a high number of possible transmission days, a large livestock population, and proximity to likely locations for the disease to enter the country via mosquito vector or human host. These areas should be monitored closely during transmission “risk seasons” so that if the virus does enter the country and begins to become established, it can be quickly controlled and eliminated before spreading further. Areas most at risk include the Baltimore and New York City metro areas as well as much of the region between these urban centers; most of Texas, especially around Houston; Florida; Atlanta; southwest Nebraska; southern California and Arizona; and the central valley of California.

  1. Ultrafast Transmission Systems using Coherent Technology

    DEFF Research Database (Denmark)

    Ludwig, Reinhold; Richter, Thomas; Palushani, Evarist;

    2011-01-01

    We review recent progress in ultrafast transmission systems. Using coherent detection for simultaneous demultiplexing and demodulation enabled single channel serial 10.2Tb/s transmission over 29km as well as transmission impairment compensation far beyond electronic speed limits.......We review recent progress in ultrafast transmission systems. Using coherent detection for simultaneous demultiplexing and demodulation enabled single channel serial 10.2Tb/s transmission over 29km as well as transmission impairment compensation far beyond electronic speed limits....

  2. Nitridation of organo-silicate glass: A self-limiting process for PVD Ta1+xN/Ta barrier formation

    International Nuclear Information System (INIS)

    Interfacial reactions of sputter-deposited Ta with a low dielectric constant Si-O-C-H material (SiCOH), and with surface-nitrided SiCOH (N-SiCOH) were investigated using X-ray photoelectron spectroscopy (XPS). The studies were carried out in a system containing a processing chamber attached to an XPS analysis chamber so that sample transport between deposition and analysis environments occurred under ultrahigh vacuum (UHV) conditions. Ta sputter deposition on unmodified SiCOH yielded an interfacial phase ∼3 nm thick composed of Ta oxide/carbide (Ta-O-C), which is known to interact only weakly with Cu. Bombardment of the vicinal SiCOH surface by 500 eV Ar+ in the presence of NH3 resulted in carbon depletion and the self-limiting nitridation of the surface, with N attachment primarily at Si sites. Subsequent Ta sputter deposition yielded reduced Ta oxide and carbide formation, and formation of a Ta-rich nitride layer of 10 A average thickness. Subsequent deposition resulted in metallic Ta formation.

  3. Barriers to clean development mechanism renewable energy projects in Mexico

    International Nuclear Information System (INIS)

    Mexico is not reaching its full potential to capture benefits from clean development mechanism (CDM) projects because of its limited market for independent power producers (IPPs) and the barriers imposed on these entities by the state-run electric utility that controls most of the country's generation and transmission. This state-run entity has pursued CDM revenues only in isolated cases where international financial assistance was given because it is bound by law to pursue the least-cost generation option for its customers. Recent changes in Mexican legislation that provide incentives for renewable energy development could open the marketplace for these types of projects. (author)

  4. 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

  5. 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.

  6. Barrier infrared detector

    Science.gov (United States)

    Ting, David Z. (Inventor); Khoshakhlagh, Arezou (Inventor); Soibel, Alexander (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2012-01-01

    A superlattice-based infrared absorber and the matching electron-blocking and hole-blocking unipolar barriers, absorbers and barriers with graded band gaps, high-performance infrared detectors, and methods of manufacturing such devices are provided herein. The infrared absorber material is made from a superlattice (periodic structure) where each period consists of two or more layers of InAs, InSb, InSbAs, or InGaAs. The layer widths and alloy compositions are chosen to yield the desired energy band gap, absorption strength, and strain balance for the particular application. Furthermore, the periodicity of the superlattice can be "chirped" (varied) to create a material with a graded or varying energy band gap. The superlattice based barrier infrared detectors described and demonstrated herein have spectral ranges covering the entire 3-5 micron atmospheric transmission window, excellent dark current characteristics operating at least 150K, high yield, and have the potential for high-operability, high-uniformity focal plane arrays.

  7. 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.

  8. 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.

  9. 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.

  10. Nonlinear magnetoinductive transmission lines

    CERN Document Server

    Lazarides, Nikos; Tsironis, G P

    2011-01-01

    Power transmission in one-dimensional nonlinear magnetic metamaterials driven at one end is investigated numerically and analytically in a wide frequency range. The nonlinear magnetic metamaterials are composed of varactor-loaded split-ring resonators which are coupled magnetically through their mutual inductances, forming thus a magnetoiductive transmission line. In the linear limit, significant power transmission along the array only appears for frequencies inside the linear magnetoinductive wave band. We present analytical, closed form solutions for the magnetoinductive waves transmitting the power in this regime, and their discrete frequency dispersion. When nonlinearity is important, more frequency bands with significant power transmission along the array may appear. In the equivalent circuit picture, the nonlinear magnetoiductive transmission line driven at one end by a relatively weak electromotive force, can be modeled by coupled resistive-inductive-capacitive (RLC) circuits with voltage-dependent cap...

  11. Adjoint accuracy for the full-Stokes ice flow model: limits to the transmission of basal friction variability to the surface

    CERN Document Server

    Martin, Nathan

    2014-01-01

    This work focuses on the numerical assessment of the accuracy of an adjoint-based gradient in the perspective of variational data assimilation and parameter identification in glaciology. Using noisy synthetic data, we quantify the ability to identify the friction coefficient for such methods with a non-linear friction law. The exact adjoint problem is solved, based on second order numerical schemes, and a comparison with the so called "self-adjoint" approximation, neglecting the viscosity dependency to the velocity (leading to an incorrect gradient), common in glaciology, is carried out. For data with a noise of $1\\%$, a lower bound of identifiable wavelengths of $10$ ice thicknesses in the friction coefficient is established, when using the exact adjoint method, while the "self-adjoint" method is limited, even for lower noise, to a minimum of $20$ ice thicknesses wavelengths. The second order exact gradient method therefore provides robustness and reliability for the parameter identification process. In othe...

  12. 交流特高压线路高抗补偿度下限的研究%Research on Lower Limit of Compensation Degree for UHVA-C Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    易强; 周浩; 计荣荣; 苏菲; 孙可; 陈稼苗

    2011-01-01

    分析了潜供电流限制、空载线路电压控制对高抗补偿度的要求,给出了从潜供电流限制与空载线路电压控制角度确定高抗补偿度下限的方法。结果表明,为达到限制潜供电流的目的,单回线路的高抗补偿容量应大于线路相问电容的无功功率,双回线路的高抗补偿容量则应大于线路相间电容无功功率和以及部分回间电容无功功率之和,故此类下限受到线路参数影响较为明显,在可能的参数变化范围内,单回线路和双回线路的此类下限最高约为55%和65%。而由空载线路电压控制所要求的高抗下限却随线路长度的增加而提高,且与线路两端落点类型关系密切。线路较短时,%To restrict both secondary arc current and no-load voltage of UHVAC transmission line, the relation between secondary arc current and compensation degree of HV shunt reactor and that between voltage of no-load line and the compensation degree are researched, and the method to determine the lower limit of compensation degree of HV shunt reactor in the viewpoint of restricting secondary arc cuffent and voltage of no-load line is given. Research results show that to restrict secondary arc current of single-circuit UHVAC line the capacity of HV shunt reactor should be higher than the capacitive power of interphase capacitance; the capacity of HV shunt reactor should be higher that the sum of capacitive power of interphase capacitance and partial capacity of inter-circuit capacitance; thus the lower limit of compensation degree of HV shunt reactor determined by the restriction of secondary arc current is evidently influenced by parameters of transmission line, and within possible parameter variation range of UHVAC transmission line, the lower limit of compensation degree of HV shunt reactor for single-circuit UHVAC line is 55% and that for double-circuit UHVAC line is 65%. The lower limit of compensation degree of HV shunt

  13. Barriers to SCM implementing

    Directory of Open Access Journals (Sweden)

    M.E. Rosli

    2008-12-01

    Full Text Available Purpose: This paper explores the barriers faced by Malaysian manufacturing companies in successfullyimplementing the Supply Chain Management (SCM. The study has highlighted some pertinent factorsperforming the barriers that are most frequently reported by the studied companies. Sixteen companies, fromservice and manufacturing companies were studied over a period of two years to assess their SCM practicesthrough survey and interview processes.Design/methodology/approach: This part discusses the research design and methodological issues upon whichthe research is based. The explanation includes two types of research methods, short survey and follow-upinterviews that were identified as being suitable to achieve the aims of this study, which is to identify the currentproblem of SCM practices within the Malaysian SMEs. Research design is a framework or plan for researchused as a guide in collecting and analysing data.Findings: The results showed that the barriers are depending on the types or group of companies business; suchas either it is an SME or a big company. The barriers inhibiting the practice of SCM can be summarized inthe following factors: partnership with suppliers, limited expertise, management commitment, understanding ofSCM, supported technologies and customer satisfaction. The findings are also compared with the results of asimilar study on SCM in other country.Practical implications: Some suggestions are also offered, which is believed to be a good strategy to the companiesto manage the SCM that will lead to sustainable competitive advantage and hence improve their market share.Originality/value: There are interesting barriers between the companies in Malaysia and other country in therespect of SCM implementation. These findings can be used by both Malaysian and other companies to worktogether or review the SCM strategies that will lead to sustainable competitive advantage and hence improvetheir business performance.

  14. Transmission eigenvalues

    Science.gov (United States)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  15. 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.

  16. Approximation of effective moisture-diffusion coefficient to characterize performance of a barrier coating

    Science.gov (United States)

    Nagai, Shingo

    2013-11-01

    We report estimation of the effective diffusion coefficient of moisture through a barrier coating to develop an encapsulation technology for the thin-film electronics industry. This investigation targeted a silicon oxide (SiOx) film that was deposited on a plastic substrate by a large-process-area web coater. Using the finite difference method based on diffusion theory, our estimation of the effective diffusion coefficient of a SiOx film corresponded to that of bulk glass that was previously reported. This result suggested that the low diffusivities of barrier films can be obtained on a mass-production level in the factory. In this investigation, experimental observations and mathematical confirmation revealed the limit of the water vapor transmission rate on the single barrier coating.

  17. 新型致密扩散障极限电流氧传感器的制备及其性能%Preparation and Propeties of New Dense Diffusion Barrier Limiting Current Oxygen Sensor

    Institute of Scientific and Technical Information of China (English)

    江浩; 简家文; 陈康; 顾媛媛

    2012-01-01

    The NiO powder was synthesized by solid phase method. According to the results of X-ray diffraction and scanning electron microscopy, the mixture of NiO and 3Y20A with mass ratio 1:1 was prepared as the mixed ion-electron conductor. A limiting current oxygen sensor using 8YSZ (8% (mole fraction) yttira stabilized zirconia) as solid electrolyte layer and the mixed ion-electron conductor as dense diffusion barrier was developed successfully via a Pt liquid agglutination method. And the properties of the sensor were tested. The results indicate that the sensor has a good oxygen measurement characteristic at 923 K and 973 K with oxygen concentration varying from 1% to 40%. It shows a good linear relationship between the limiting current of sensor and oxygen concentration when oxygen concentration was in the range of 1%-25%. The response time curves show that the sensor has good repeatability and fast response time at different oxygen concentrations.%采用固相法制备NiO粉体。根据X射线衍射分析和扫描电子显微镜观察结果,用NiO和3Y20A[含有20%(质量分数)氧化铝的3%(摩尔分数)Y203稳定的Zr02】质量比为1:1制备的混合导体作为致密扩散障层,采用Pt浆料粘合法将其与8YSZ[8%(摩尔分数)Y203稳定的ZrO2】固体电解质叠层制成致密扩散障型极限电流氧传感器,对其敏感特性进行了研究。结果表明:该传感器在923K和973K、氧气体积分数为1%~40%范围内具有良好的测氧特性;在氧气体积分数为1%~25%范围内极限电流与氧体积分数之间存在良好的线性关系。响应时间曲线表明:在不同氧体积分数下传感器重复性好、响应时间快。

  18. Transmissible amyloid.

    Science.gov (United States)

    Tjernberg, L O; Rising, A; Johansson, J; Jaudzems, K; Westermark, P

    2016-08-01

    There are around 30 human diseases associated with protein misfolding and amyloid formation, each one caused by a certain protein or peptide. Many of these diseases are lethal and together they pose an enormous burden to society. The prion protein has attracted particular interest as being shown to be the pathogenic agent in transmissible diseases such as kuru, Creutzfeldt-Jakob disease and bovine spongiform encephalopathy. Whether similar transmission could occur also in other amyloidoses such as Alzheimer's disease, Parkinson's disease and serum amyloid A amyloidosis is a matter of intense research and debate. Furthermore, it has been suggested that novel biomaterials such as artificial spider silk are potentially amyloidogenic. Here, we provide a brief introduction to amyloid, prions and other proteins involved in amyloid disease and review recent evidence for their potential transmission. We discuss the similarities and differences between amyloid and silk, as well as the potential hazards associated with protein-based biomaterials. PMID:27002185

  19. Transport of two-dimensional electrons through magnetic barriers

    CERN Document Server

    Kubrak, V

    2001-01-01

    scattering rate is an important probe for the unusual electron dynamics inside the barrier, which is different for different barrier types. It is studied how states bound within the barrier or channelled along zero-field contour lines affect the transport through the barriers. To facilitate the interpretation, the experimental results are compared to semi-ballistic Monte Carlo simulations. In the semi-ballistic regime, the barrier resistance of small-amplitude simple barriers is found to be mainly due to ballistic reflection and to be almost independent of the scattering rate. For opaque barriers, scattering-assisted transmission, which results in a decrease of the resistance with increasing scattering rate, and orbits skipping along the edge of the channel are found to be important. In contrast, the resistance of barriers with a zero-field contour increases with increasing scattering rate, which is ascribed to scattering into the snake orbits that are channelled along the contour. It is also demonstrated how...

  20. Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Kaeaeriaeinen, Tommi O., E-mail: tommi.kaariainen@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Cameron, David C., E-mail: david.cameron@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Lahtinen, Kimmo, E-mail: kimmo.lahtinen@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Johansson, Petri, E-mail: petri.johansson@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland)

    2011-03-01

    One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O{sub 2}TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O{sub 2}TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

  1. 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 Español (Spanish) Recommend on Facebook ...

  2. 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 AIMS.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Transmission Lines or Poles, Electric dataset, was produced all or in part from Other information as of 2004. It is described as 'Electric transmission lines...

  3. Translating barriers into potential improvements

    DEFF Research Database (Denmark)

    Altintzoglou, Themistoklis; Hansen, Karina Birch; Valsdottir, Thora;

    2010-01-01

    and Iceland. The results were then linked to the Stage-Gate model for consumer-based new product development (NPD). Findings: The participants thought of seafood as either healthy or convenient, although there The participants thought of seafood as either healthy or convenient, although there were concerns....... An increase in seafood availability coupled with lower prices would encourage these consumers to add seafood to their diet. Research limitations/implications: Purchase-point-marketing and habitual behaviour were Purchase-point-marketing and habitual behaviour were found to implicitly skew planned behaviour......Purpose: The aim of this study is to explore potential barriers to seafood consumption by The aim of this study is to explore potential barriers to seafood consumption by young adults and the parents of young children. Knowledge of these barriers will be used to assist the development of new...

  4. 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.

  5. Fault-Tolerant Transmission Protocol for Distant Agricultural Image Acquisition

    OpenAIRE

    Jian Chen; Deqin Xiao; Dongmin Liu; Xiaoqing Jiang

    2013-01-01

    To solve the problem of the high cost in the GPRS communication and the limit transmission distance of WiFi, a transmission scheme for distant agriculture image acquisition was designed based on digital transmission radio in this paper. However, the majority of current digital transmission radio was designed for a small amount of data transmission. It could get a greater transmission distance with the help of the digital transmission radio, but the signal interference increased heavily when t...

  6. Silicon oxide diffusion barrier coatings on polypropylene

    International Nuclear Information System (INIS)

    In this study the influence of process conditions for the plasma-enhanced chemical vapor deposition of SiOx diffusion barrier coatings on polypropylene (PP) is investigated and compared to results obtained on polyethylene terephthalate (PET). It was observed that the thermal load during deposition is much more crucial in the case of PP. If the thermal load is not the limiting factor, the composite parameter (CP) energy input per mass of precursor showed to be valuable to describe plasma conditions at constant oxygen to monomer ratio. Low oxygen transmission rates (OTRs) of 5.1 ± 3.6 and 0.3 ± 0.1 cm3/m2day/atm were achieved on PP and PET foil, respectively, for an optimal CP of 4.1 x 105 J/g. Fourier transform infrared (FTIR) spectroscopy revealed that low carbon and silanol content is necessary for good barrier performance. Low RF power, necessary to reduce thermal load on PP, can be compensated by increasing the oxygen to monomer ratio. For favorable plasma conditions, the dependence of the OTR on the coating thickness follows a similar trend for both substrate materials with a critical thickness of approximately 12 nm. The residual permeation can be correlated to the defect density at each stage of film growth by means of a simple correlation. Further support for permeation through defects is found by the activated rate theory, since the apparent activation energy of oxygen permeation is below typical values of amorphous glasses and remains unchanged due to the deposition of SiOx on both substrates.

  7. Wireless Power Transmission

    OpenAIRE

    Pragati S. Chawardol; Deepali R. Badre ,; , Mithul S. There

    2014-01-01

    A great concern has been voiced in recent years over the extensive use of energy, the limited supply of resourses, and the pollution of the environment from the use of present energy conversion systems. Electrical power accounts for much of the energy consumed. One of the major issue in power system is the losses occurs during the transmission and distribution of electrical power. As the demand increases day by day, the power generation increases and the power loss is also increas...

  8. Wavevector filtering through single-layer and bilayer graphene with magnetic barrier structures

    Science.gov (United States)

    Masir, M. Ramezani; Vasilopoulos, P.; Peeters, F. M.

    2008-12-01

    We show that the angular range of the transmission through magnetic barrier structures can be efficiently controlled in single-layer and bilayer graphenes and this renders the structure's efficient wavevector filters. As the number of magnetic barriers increases, this range shrinks, the gaps in the transmission versus energy become wider, and the conductance oscillates with the Fermi energy.

  9. 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. PMID:26978066

  10. Assessment of blood-retinal barrier integrity.

    Science.gov (United States)

    Vinores, S A

    1995-01-01

    The blood-retinal barrier consists of two components which are comprised of the retinal vascular endothelium and the retinal pigment epithelium, respectively. Its functional integrity can be recognized by tight junctions between these cells with a paucity of endocytic vesicles within them and the presence of the molecules that regulate the ionic and metabolic gradients that constitute the barrier. The barrier is compromised in several disease processes and by a variety of agents, but in most cases the location and mechanism for barrier failure is not understood. Perfusion with a variety of radiolabeled tracer molecules, vitreous fluorophotometry, or magnetic resonance imaging can be used to quantitate blood-retinal barrier leakage. Fluorescein angiography or magnetic resonance imaging can localize sites of leakage in vivo with limited resolution. Evans blue dye can be used to visualize blood-retinal barrier failure in gross pathological specimens and immuno-histochemical labeling of serum proteins such as albumin or fibrinogen can be used to localize sites of blood-retinal barrier breakdown by light microscopy. Tracers such as horseradish peroxidase, microperoxidase, or lanthanum, or the immunocytochemical demonstration of albumin can be used to reveal blood-retinal barrier breakdown at the ultrastructural level and provide insights into the mechanisms involved. This review discusses the advantages and limitations of each of these methods to aid in selection of the appropriate techniques to derive the desired information.

  11. Crossing species barrier by PrPSc replication in vitro generates new infectious prions

    OpenAIRE

    Castilla, Joaquín; Gonzalez-Romero, Dennisse; Saá, Paula; Morales, Rodrigo; Castro, Jorge; Soto, Claudio

    2008-01-01

    Prions are unconventional infectious agents composed exclusively by the misfolded prion protein (PrPSc), which transmits the disease by propagating its abnormal conformation to the cellular prion protein (PrPC). A key characteristic of prions is their species barrier, by which prions from one species can only infect a limited number of other species. Here we report the generation of novel infectious prions by inter-species transmission of PrPSc misfolding in vitro. Hamster PrPC misfolded by m...

  12. Transparent Metal-Organic Framework/Polymer Mixed Matrix Membranes as Water Vapor Barriers.

    Science.gov (United States)

    Bae, Youn Jue; Cho, Eun Seon; Qiu, Fen; Sun, Daniel T; Williams, Teresa E; Urban, Jeffrey J; Queen, Wendy L

    2016-04-27

    Preventing the permeation of reactive molecules into electronic devices or photovoltaic modules is of great importance to ensure their life span and reliability. This work is focused on the formation of highly functioning barrier films based on nanocrystals (NCs) of a water-scavenging metal-organic framework (MOF) and a hydrophobic cyclic olefin copolymer (COC) to overcome the current limitations. Water vapor transmission rates (WVTR) of the films reveal a 10-fold enhancement in the WVTR compared to the substrate while maintaining outstanding transparency over most of the visible and solar spectrum, a necessary condition for integration with optoelectronic devices. PMID:27071544

  13. Transmission line capital costs

    International Nuclear Information System (INIS)

    The displacement or deferral of conventional AC transmission line installation is a key benefit associated with several technologies being developed with the support of the U.S. Department of Energy's Office of Energy Management (OEM). Previous benefits assessments conducted within OEM have been based on significantly different assumptions for the average cost per mile of AC transmission line. In response to this uncertainty, an investigation of transmission line capital cost data was initiated. The objective of this study was to develop a database for preparing preliminary estimates of transmission line costs. An extensive search of potential data sources identified databases maintained by the Bonneville Power Administration (BPA) and the Western Area Power Administration (WAPA) as superior sources of transmission line cost data. The BPA and WAPA data were adjusted to a common basis and combined together. The composite database covers voltage levels from 13.8 to 765 W, with cost estimates for a given voltage level varying depending on conductor size, tower material type, tower frame type, and number of circuits. Reported transmission line costs vary significantly, even for a given voltage level. This can usually be explained by variation in the design factors noted above and variation in environmental and land (right-of-way) costs, which are extremely site-specific. Cost estimates prepared from the composite database were compared to cost data collected by the Federal Energy Regulatory Commission (FERC) for investor-owned utilities from across the United States. The comparison was hampered because the only design specifications included with the FERC data were voltage level and line length. Working within this limitation, the FERC data were not found to differ significantly from the composite database. Therefore, the composite database was judged to be a reasonable proxy for estimating national average costs

  14. Multilayer coatings for flexible high-barrier materials

    Science.gov (United States)

    Vaško, Karol; Noller, Klaus; Mikula, Milan; Amberg-Schwab, Sabine; Weber, Ulrike

    2009-06-01

    A multilayer, flexible, and transparent high-barrier system based on flexible plastic foils, polyethyleneterephthalate (PET) and ethylene-tetrafluoroethylene-copolymer (ETFE), combined with vacuum-deposited, inorganic SiOx layers and hybrid ORMOCER® varnish layers were prepared in different orders on a semiproduction level. Barrier properties of prepared systems, as water vapour transmission (WVTR) and oxygen transmission (OTR), were measured and studied in connection with surface energy, surface topography, and water vapour adsorption properties. Correlations among layers sequence, barrier properties, and other parameters are presented, including some basic principles of permeation of substances through multilayer barrier systems. A combination of several inorganic and hybrid varnish layers is necessary to achieve the technological demands from a barrier standpoint. It is easier to suppress the oxygen transport than the water transport, due to the additional active penetration of water through hydrogen bonds and silanol creations at oxide interfaces, capillary condensation, and swelling with high internal pressure, leading to new defects.

  15. How long does a wave packet interact with a potential barrier?

    CERN Document Server

    Begliuomini, A; Begliuomini, Andrea; Bracci, Luciano

    1996-01-01

    We examine the time evolution of a packet approaching a one dimensional potential barrier. The times required for the appearance of a reflected or a transmitted packet are definitely different from the reflection and transmission times presented in the literature for stationary problems. The depletion rate of the packet trapped within the barrier region depends only on the properties of the barrier. We propose new definitions for the dwell, reflection and transmission times suitable for a packet.

  16. The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels.

    Science.gov (United States)

    Lehner, C; Gehwolf, R; Ek, J C; Korntner, S; Bauer, H; Bauer, H C; Traweger, A; Tempfer, H

    2016-01-01

    Tissue barriers function as "gate keepers" between different compartments (usually blood and tissue) and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF)-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB). By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies. PMID:27227787

  17. 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......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...... analysis with operational safety management....

  18. Safety- barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2008-01-01

    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 of safety-barrier diagrams to other methods such as fault...... 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....

  19. 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...... to a constitutive notion of communication. Findings – The study brings forth four main findings: from the CCO view, organizations are constituted by several, partly dissonant, and potentially contradictory communicative practices. From that viewpoint, the potential impact of CSR communication becomes a matter...

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

    Indian Academy of Sciences (India)

    S V S Sastry; S Kailas; A K Mohanty; A Saxena

    2005-01-01

    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 adiabatic barriers are consistent with the adiabatic fusion barriers derived from the modified Wilzynska–Wilzynski prescription. The fusion barrier systematics has been obtained for a wide range of heavy-ion systems.

  1. Evidence of localized wave transmission

    International Nuclear Information System (INIS)

    LLNL [Lawrence Livermore National Lab.] experiments to test the feasibility of launching an acoustic, directed-energy pulse train (ADEPT) in water have demonstrated localized transmission of wave energy far beyond the classical Rayleigh length that defines the boundary between near-field and far-field transmission for Gaussian (diffraction-limited) pulses. The results of the experiments are in excellent agreement with computer simulations

  2. Barriers to multi-sectoral collaboration in the prevention of mother-to-child transmission of acquired immune deficiency syndrome%预防艾滋病母婴传播管理中多部门合作的障碍

    Institute of Scientific and Technical Information of China (English)

    夏建红; 王临虹; 赵庆国

    2009-01-01

    目的:了解在预防艾滋病母婴传播管理中,各医疗保健服务机构在合作中的需求和相关的问题,深入了解多部门合作的障碍及其影响因素.方法:主要采用定性研究的方法:数据收集包括文献回顾研究、半结构深度访谈、焦点小组讨论、参与性观察、案例分析等;数据分析采用描述、归类、联系等定性研究分析的方法,综合归纳出一个相互联系的概念框架.结果:在预防艾滋病母婴传播的管理中有四类影响多部门合作的障碍:参与合作的能力不足;参与的各部门在合作中的需求不能满足;职能交叉、角色不明、不能承担共同的责任;缺少理解和信任,不能达成共识.在每一类合作障碍中又有若干个影响因素.这些因素之间相互作用,共同形成了合作障碍的框架.结论:在当前预防艾滋病母婴传播的管理中,有许多因素影响多部门的合作,需要制定相关的政策,明确职责,克服障碍,促进多部门的合作.%Objective: To understand the demand and related questions of collaboration of clinical health care organizations in the prevention of mother-to-child transmission of acquired immune deficiency syndrome (AIDS), explore the barriers and effect factors of multi-sectoral collaboration. Methods: Qualitative investigation was used in the study. The primary data collection methods were semi-structured in-depth interviews and focus groups, with stakeholder identification, participation observation and case study. Data analysis in-cluded description, classification and contact. Results: Four barriers were found in the study: lack of capacity for collaboration; stakehold-era'different demands for collaboration; stakeholders'undefined roles in collaboration and lack of trust. Each of these barriers comprised a number of effect factors. Conclusion: In the management of prevention of mother-to-child transmission of AIDS, many factors affect the multi-sectoral collaboration

  3. Patient advocacy: barriers and facilitators

    Directory of Open Access Journals (Sweden)

    Nikravesh Mansoure

    2006-03-01

    Full Text Available 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 Iranian nurses. Method This study was conducted by grounded theory method. Participants were 24 Iranian registered nurses working in a large university hospital in Tehran, Iran. Semi-structured interviews were used for data collection. All interviews were transcribed verbatim and simultaneously Constant comparative analysis was used according to the Strauss and Corbin method. Results Through data analysis, several main themes emerged to describe the factors that hindered or facilitated patient advocacy. Nurses in this study identified powerlessness, lack of support, law, code of ethics and motivation, limited communication, physicians leading, risk of advocacy, royalty to peers, and insufficient time to interact with patients and families as barriers to advocacy. As for factors that facilitated nurses to act as a patient advocate, it was found that the nature of nurse-patient relationship, recognizing patients' needs, nurses' responsibility, physician as a colleague, and nurses' knowledge and skills could be influential in adopting the advocacy role. Conclusion Participants believed that in this context taking an advocacy role is difficult for nurses due to the barriers mentioned. Therefore, they make decisions and act as a patient's advocate in any situation concerning patient needs and status of barriers and facilitators. In most cases, they can not act at an optimal level; instead they accept only what they can do, which we called 'limited advocacy' in

  4. 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.

  5. Influence of layer type and order on barrier properties of multilayer PECVD barrier coatings

    Science.gov (United States)

    Bahroun, K.; Behm, H.; Mitschker, F.; Awakowicz, P.; Dahlmann, R.; Hopmann, Ch

    2014-01-01

    Due to their macromolecular structure, plastics are limited in their scope of application whenever high barrier functionality against oxygen and water vapour permeation is required. One solution is the deposition of thin silicon oxide coatings in plasma-enhanced chemical vapour deposition (PECVD) processes. A way to improve performance of barrier coatings is the use of multilayer structures built from dyad layers, which combine an inorganic barrier layer and an organic intermediate layer. In order to investigate the influence of type and number of dyads on the barrier performance of coated 23 µm PET films, different dyad setups are chosen. The setups include SiOCH interlayers and SiOx-barrier layers deposited using the precursor hexamethyldisiloxane (HMDSO). A single reactor setup driven in pulsed microwave plasma (MW) mode as well as capacitively coupled plasma (CCP) mode is chosen. In this paper the effects of a variation in intermediate layer recipe and stacking order using dyad setups on the oxygen barrier properties of multilayer coatings are discussed with regard to the chemical structure, morphology and activation energy of the permeation process. Changes in surface nano-morphology of intermediate layers have a strong impact on the barrier properties of subsequent glass-like coatings. Even a complete failure of the barrier is observed. Therefore, when depositing multilayer barrier coatings, stacking order has to be considered.

  6. Influence of layer type and order on barrier properties of multilayer PECVD barrier coatings

    International Nuclear Information System (INIS)

    Due to their macromolecular structure, plastics are limited in their scope of application whenever high barrier functionality against oxygen and water vapour permeation is required. One solution is the deposition of thin silicon oxide coatings in plasma-enhanced chemical vapour deposition (PECVD) processes. A way to improve performance of barrier coatings is the use of multilayer structures built from dyad layers, which combine an inorganic barrier layer and an organic intermediate layer. In order to investigate the influence of type and number of dyads on the barrier performance of coated 23 µm PET films, different dyad setups are chosen. The setups include SiOCH interlayers and SiOx-barrier layers deposited using the precursor hexamethyldisiloxane (HMDSO). A single reactor setup driven in pulsed microwave plasma (MW) mode as well as capacitively coupled plasma (CCP) mode is chosen. In this paper the effects of a variation in intermediate layer recipe and stacking order using dyad setups on the oxygen barrier properties of multilayer coatings are discussed with regard to the chemical structure, morphology and activation energy of the permeation process. Changes in surface nano-morphology of intermediate layers have a strong impact on the barrier properties of subsequent glass-like coatings. Even a complete failure of the barrier is observed. Therefore, when depositing multilayer barrier coatings, stacking order has to be considered. (paper)

  7. 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.

  8. Scattering of topological solitons on holes and barriers

    OpenAIRE

    Piette, B.; Zakrzewski, W. J.; Brand, J.

    2005-01-01

    We study the scattering properties of topological solitons on obstructions in the form of holes and barriers. We use the 'new baby Skyrme' model in (2+1) dimensions and we model the obstructions by making the coefficient of the baby skyrme model potential - position dependent. We find that that the barrier leads to the repulsion of the solitons (for low velocities) or their complete transmission (at higher velocities) with the process being essentially elastic. The hole case is different; for...

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

    Science.gov (United States)

    Granstrom, Jimmy Erik

    The air sensitivity of organic electronic devices has delayed the broad commercialization of the printed "plastics" electronics technology. The vacuum deposition methods used to fabricate multi-layers which fulfill the encapsulation requirements for plastic electronic devices are complex and expensive. Fully printed "plastic" electronics requires the development of encapsulation architectures which comprise solution deposited barriers and/or low-cost free-standing barrier films based on polymers, e.g. poly ethylene terephthalate (PET). One way to reach this goal is the insertion of contaminant-free (e.g. pure N2) gas-phase spacers between free-standing barrier films in a multilayer structure. The spacers themselves do not exhibit any barrier properties (diffusion of gas permeants in a gas phase is orders of magnitude faster than in a solid), but they delay the attainment of steady state. The spacer also reduces the chemical potential gradient across downstream barrier layers during the transient regime, reducing permeation rate to the device. Furthermore, if sorption is not fully equilibrated and introduces a kinetic barrier to transport, the additional sorption and desorption steps needed for permeant to reach the device may also slow the steady-state permeation rate. Encapsulation architectures utilizing both single-matrix (without nitrogen spacers) and multiple-matrix structures (with nitrogen spacers) were fabricated in this study, including Russian Doll structures utilizing pairs of free-standing barrier films and epoxy seals separated by nitrogen spacers. This structure enables the use of low-cost epoxy to attach two or more free-standing barrier films to a substrate with improved barrier performance. The performance of various Russian Doll encapsulations was evaluated with the calcium thin film optical transmission test, showing improved performance of the Russian doll configuration relative to a non-nested barrier/spacer architecture, and demonstrating that

  10. Complex quantum trajectories for barrier scattering

    Science.gov (United States)

    Rowland, Bradley Allen

    We have directed much attention towards developing quantum trajectory methods which can accurately predict the transmission probabilities for a variety of quantum mechanical barrier scattering processes. One promising method involves solving the complex quantum Hamilton-Jacobi equation with the Derivative Propagation Method (DPM). We present this method, termed complex valued DPM (CVDPM(n)). CVDPM(n) has been successfully employed in the Lagrangian frame to accurately compute transmission probabilities on 'thick' one dimensional Eckart and Gaussian potential surfaces. CVDPM(n) is able to reproduce accurate results with a much lower order of approximation than is required by real valued quantum trajectory methods, from initial wave packet energies ranging from the tunneling case (Eo = 0) to high energy cases (twice the barrier height). We successfully extended CVDPM(n) to two-dimensional problems (one translational degree of freedom representing an Eckart or Gaussian barrier coupled to a vibrational degree of freedom) in the Lagrangian framework with great success. CVDPM helps to explain why barrier scattering from "thick" barriers is a much more well posed problem than barrier scattering from "thin" barriers. Though results in these two cases are in very good agreement with grid methods, the search for an appropriate set of initial conditions (termed an 'isochrone) from which to launch the trajectories leads to a time-consuming search problem that is reminiscent of the root-searching problem from semi-classical dynamics. In order to circumvent the isochrone problem, we present CVDPM(n) equations of motion which are derived and implemented in the arbitrary Lagrangian-Eulerian frame for a metastable potential as well as the Eckart and Gaussian surfaces. In this way, the isochrone problem can be circumvented but at the cost of introducing other computational difficulties. In order to understand why CVDPM may give better transmission probabilities than real valued

  11. Zika and Sexual Transmission

    Science.gov (United States)

    ... Address What's this? Submit What's this? Submit Button Zika and Sexual Transmission Language: English Español Português ... Healthcare Providers: Sexual Transmission of Zika Basics of Zika Virus and Sex Transmission Zika can be passed ...

  12. 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

  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. 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.

  15. Permanent isolation surface barrier development plan

    International Nuclear Information System (INIS)

    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 provenclose 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. 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.

  17. Complementary barrier infrared detector (CBIRD)

    Science.gov (United States)

    Ting, David Z. (Inventor); Bandara, Sumith V. (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2013-01-01

    An infrared detector having a hole barrier region adjacent to one side of an absorber region, an electron barrier region adjacent to the other side of the absorber region, and a semiconductor adjacent to the electron barrier.

  18. 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 by...

  19. Recycler barrier RF buckets

    CERN Document Server

    Bhat, C M

    2012-01-01

    The Recycler Ring at Fermilab uses a barrier rf system for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf systems, 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.

  20. 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.

  1. A resistance formula for coherent multi-barrier structures

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhi-Chen; Yang Jian-Hong

    2007-01-01

    Using the Landauer formula and the quantum S-matrix scattering theory, we derive a resistance formula for multi-barrier structure under phase coherent transmission condition. This formula shows that when the transport is coherent, the potential wells of the structure are just like conductors contributing to the overall resistance. And because the resistance formula is derived based on the scattering theory, the barrier resistance will change with the number of scattering centres (i.e. the number of barriers) in the structure.

  2. Cathode-Electrolyte Interfaces with CGO Barrier Layers in SOFC

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Hjelm, Johan; Menon, Mohan;

    2010-01-01

    10) barrier layer, the other had a barrier layer deposited by pulsed laser deposition (PLD) CGO10. Scanning electron microscopy, transmission electron microscopy (TEM), and electron backscattered diffraction (EBSD) investigations conclude that the major source of the cell performance difference is...... attributed to CGO–YSZ interdiffusion in the sprayed-cosintered barrier layer. From TEM and EBSD work, a dense CGO10 PLD layer is found to be deposited epitaxially on the 8YSZ electrolyte substrate—permitting a small amount of SrZrO3 formation and minimizing CGO–YSZ interdiffusion....

  3. Barriers to wind power exports from the Maritime provinces to the US northeast

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, J. [Power Advisory LLC, Carlisle, MA (United States)

    2009-07-01

    This presentation discussed a study that evaluated wind energy export potential from the Maritime provinces to the northeastern United States. The study assessed key market issues likely to affect the exports. The study showed that the Maritime provinces are capable of generating 5500 to 7500 MW of wind. The current electricity system is capable of integrating 2100 MW. Wind power integration between the 2 regions would require transmission upgrades, increased transmission capacity, and better coordination between system operators. Barriers to exports from the Maritimes include limited capacity on existing interties and high transmission tariffs. Uniform transmission tariffs are needed throughout the Maritime provinces. Coordination and integration of operators and utilities is needed to reduce the costs of wind power integration. Increased wind power production reduces price risks related to high energy prices. It was concluded that wind power is a cost-effective method of providing renewable and low carbon dioxide (CO{sub 2}) generation electricity in the northeastern United States. tabs., figs.

  4. The interaction time of a packet with a potential barrier

    International Nuclear Information System (INIS)

    They study the evolution of a wave packet impinging onto a one-dimensional potential barrier. The transmission and reflection times discussed in the literature for stationary states do not correspond to the times required for the emergence of a transmitted or a reflected packet. They propose new definitions for the interaction time and the transmission and reflection times which are suitable for packets and fit better the actual time evolution of the packet

  5. Barriers to international supply chain management in Iranian flower industry

    OpenAIRE

    Arash Riasi

    2015-01-01

    The main purpose of this study was to determine the major barriers to international supply chain management in Iranian flower industry. The results of the research revealed that the most important barrier is lack of investment in Iranian flower distribution sector. The results also indicated that the second most important barrier to international supply chain management in Iranian flower industry might be the rules that limit the presence of international distributors in the country’s flower ...

  6. [Vascular endothelial Barrier Function].

    Science.gov (United States)

    Ivanov, A N; Puchinyan, D M; Norkin, I A

    2015-01-01

    Endothelium is an important regulator of selective permeability of the vascular wall for different molecules and cells. This review summarizes current data on endothelial barrier function. Endothelial glycocalyx structure, its function and role in the molecular transport and leukocytes migration across the endothelial barrier are discussed. The mechanisms of transcellular transport of macromolecules and cell migration through endothelial cells are reviewed. Special section of this article addresses the structure and function of tight and adherens endothelial junction, as well as their importance for the regulation of paracellular transport across the endothelial barrier. Particular attention is paid to the signaling mechanism of endothelial barrier function regulation and the factors that influence on the vascular permeability.

  7. Barriers to Effective Listening.

    Science.gov (United States)

    Hulbert, Jack E.

    1989-01-01

    Discusses the following barriers which interfere with listening efficiency: content, speaker, medium, distractions, mindset, language, listening speed, and feedback. Suggests ways to combat these obstacles to accurate comprehension. (MM)

  8. Overcoming Intercultural Communication Barriers.

    Science.gov (United States)

    Hulbert, Jack E.

    1994-01-01

    Describes an activity that helps students overcome the multicultural barriers that might be encountered in dealing with people from various cultures in a global economy. Outlines instructions, reporting procedures, principles to emphasize, and time required for the exercise. (HB)

  9. Information barriers and authentication

    International Nuclear Information System (INIS)

    Acceptance of nuclear materials into a monitoring regime is complicated if the materials are in classified shapes or have classified composition. An attribute measurement system with an information barrier can be emplo,yed to generate an unclassified display from classified measurements. This information barrier must meet two criteria: (1) classified information cannot be released to the monitoring party, and (2) the monitoring party must be convinced that the unclassified output accurately represents the classified input. Criterion 1 is critical to the host country to protect the classified information. Criterion 2 is critical to the monitoring party and is often termed the 'authentication problem.' Thus, the necessity for authentication of a measurement system with an information barrier stems directly from the description of a useful information barrier. Authentication issues must be continually addressed during the entire development lifecycle of the measurement system as opposed to being applied only after the system is built.

  10. Baseline survey of pregnant women 's knowledge of treat-ment to prevent mother-to-child human immuno-deficien-cy virus transmission in a resource limited setting

    Institute of Scientific and Technical Information of China (English)

    Stephen Onwere; Obioha Okoro; Bright Chigbu; Chuks Kamanu; Christian Aluka; Paul Feyi-Wa-boso

    2008-01-01

    Despite continuing advances in scientific knowledge about treatments to prevent mother-to-child (MTCT)of the human immune deficiency virus (HIV),there is a paucity of data on pregnant women's knowledge of treat-ments to prevent MTCT of HIV in Aba,South Eastern Nigeria.We investigated pregnant women's knowledge of the availability of treatments to prevent MTCT of HIV in the low resourced setting of Aba town in South Eastern Nigeria.A descriptive study involving 100 consecutive and consenting patients at the antenatal clinic of Abia State University Teaching Hospital (ABSUTH),Aba,South Eastern Nigeria over the period 1st November, 2007 to 30th November,2007.Using a structured questionnaire,the respondents'sociodemographic data were obtained as well as their knowledge of the availability of treatments to prevent mother to child HIV transmission in pregnant women and self-reported data on their having ever tested for HIV.Knowledge regarding availability of treatment to prevent mother to child transmission of HIV was good as 95% of the respondents were aware that such treatment was available.Knowledge that treatment is available to help someone infected by HIV to live longer was also good as 96% of the respondents were aware of the availability of such treatment.Seventy one percent of the respondents had ever tested for HIV.The levels of knowledge regarding the availability of treatment to prevent mother to child HIV transmission and to help someone infected with HIV are good.Thus, utilization of anti-retroviral prophylaxis amongst HIV infected pregnant women in this community would be ex-pected to be high if the drugs were available.This will reduce the impact of HIV,especially in children.

  11. Model assessment of protective barriers: Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, M.J.; Rockhold, M.L.; Holford, D.J.

    1992-02-01

    Radioactive waste exists at the US Department of Energy's (DOE's) Hanford Site in a variety of locations, including subsurface grout and tank farms, solid waste burial grounds, and contaminated soil sites. Some of these waste sites may need to be isolated from percolating water to minimize the potential for transport of the waste to the ground water, which eventually discharges to the Columbia River. Multilayer protective barriers have been proposed as a means of limiting the flow of water through the waste sites (DOE 1987). A multiyear research program (managed jointly by Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company for the DOE) is aimed at assessing the performance of these barriers. One aspect of this program involves the use of computer models to predict barrier performance. Three modeling studies have already been conducted and a test plan was produced. The simulation work reported here was conducted by PNL and extends the previous modeling work. The purpose of this report are to understand phenomena that have been observed in the field and to provide information that can be used to improve hydrologic modeling of the protective barrier. An improved modeling capability results in better estimates of barrier performance. Better estimates can be used to improve the design of barriers and the assessment of their long-term performance.

  12. 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.

  13. 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 to the ...

  14. 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 acad

  15. The interaction between tide and salinity barriers

    Directory of Open Access Journals (Sweden)

    Patchanok Srivihok

    2003-11-01

    Full Text Available Presently, there is a number of salinity barrier utilization and this kind of structure becomes more common in estuarine areas. However, the construction of barrier at the river mouth or inside the river results in amplification of tide due to creation of standing tide at the barrier. This standing tide creates two major problems, namely, the overspill of salinewater during high water and bank erosion during low water along the tidal reach downstream of the barrier. In this study, the analytical model is developed to determine the river hydraulic behaviors which affects by tide, river flow and barrier structure of the Bang Pakong River, Thailand. The analytical model of tide and river flow of the Chao Phraya River is adopted and adjusted to determine the tide characteristics modified by river flow. Moreover, the analytical model of tide and salinity barrier would then be developed by cooperating of the analytical model of tide and river flow interaction together with tidal flow cooscillating tide theory. It is found from this study that the analytical model of the Chao Phraya River which is suitable for high freshwater discharge underestimates damping modulus and friction slope which requires adjustment for low freshwater discharge of the Bang Pakong River. The analytical model of tide and salinity barrier can be finally used to predict the water level downstream of the barrier. The model overestimated the water level fluctuation during the unsteady flow from upstream which may be because of the assumption of steady flow condition in the model development due to limited data available after the construction.

  16. Dynamically prioritized progressive transmission

    Science.gov (United States)

    Blanford, Ronald

    1992-04-01

    Retrieval of image data from a centralized database may be subject to bandwidth limitations, whether due to a low-bandwidth communications link or to contention from simultaneous accesses over a high-bandwidth link. Progressive transmission can alleviate this problem by encoding image data so that any prefix of the data stream approximates the complete image at a coarse level of resolution. The longer the prefix, the finer the resolution. In many cases, as little at 1 percent of the image data may be sufficient to decide whether to discard the image, to permit the retrieval to continue, or to restrict retrieval to a subsection of the image. Our approach treats resolution not as a fixed attribute of the image, but rather as a resource which may be allocated to portions of the image at the direction of a user-specified priority function. The default priority function minimizes error by allocating more resolution to regions of high variance. The user may also point to regions of interest requesting priority transmission. More advanced target recognition strategies may be incorporated at the user's discretion. Multispectral imagery is supported. The user engineering implications are profounded. There is immediate response to a query that might otherwise take minutes to complete. The data is transmitted in small increments so that no single user dominates the communications bandwidth. The user-directed improvement means that bandwidth is focused on interesting information. The user may continue working with the first coarse approximations while further image data is still arriving. The algorithm has been implemented in C on Sun, Silicon Graphics, and NeXT workstations, and in Lisp on a Symbolics. Transmission speeds reach as high as 60,000 baud using a Sparc or 68040 processor when storing data to memory; somewhat less if also updating a graphical display. The memory requirements are roughly five bytes per image pixel. Both computational and memory costs may be reduced

  17. Transmission Lines Emulating Moving Media

    CERN Document Server

    Vehmas, Joni; Tretyakov, Sergei

    2014-01-01

    In this paper, we show how the electromagnetic phenomena in moving magnetodielectric media can be emulated using artificial composite structures at rest. In particular, we introduce nonreciprocal periodically loaded transmission lines which support waves obeying the same rules as plane electromagnetic waves in moving media. Because the actual physical structure is at rest, in these transmission lines there are no fundamental limitations on the velocity values, which may take values larger than the speed of light or even complex values (considering complex amplitudes in the time-harmonic regime). An example circuit of a unit cell of a "moving" transmission line is presented and analyzed both numerically and experimentally. The special case of composite right/left handed host line is also studied numerically. Besides the fundamental interest, the study is relevant for potential applications in realizing engineered materials for various transformations of electromagnetic fields.

  18. Progress toward interruption of wild poliovirus transmission - worldwide, 2009.

    Science.gov (United States)

    2010-05-14

    In 1988, an estimated 350,000 cases of poliomyelitis were occurring annually worldwide. By 2005, because of global vaccination efforts, indigenous transmission of wild poliovirus (WPV) types 1 and 3 (WPV1 and WPV3) had been eliminated from all but four countries (Afghanistan, India, Nigeria, and Pakistan). No cases of WPV type 2 have been reported since 1999. This report describes progress toward global WPV eradication during 2009 and updates previous reports. During 2009 a total of 1,606 cases of WPV infection were reported, compared with 1,651 in 2008. WPV3 incidence increased 67%, to 1,124 cases, compared with 675 in 2008. However, WPV1 incidence decreased 51%, to 482 cases in 2009, compared with 976 cases in 2008. In India, nearly all polio cases in 2009 were reported in high-risk districts in western Uttar Pradesh and central Bihar. In Afghanistan and Pakistan, WPV circulation in high-risk districts continued because of difficulties vaccinating children in conflict-affected areas and operational limitations in parts of Pakistan. In Nigeria, cases decreased by 51%, to 388 cases in 2009, compared with 798 in 2008. During 2009, outbreaks from importation of WPV affected 19 previously polio-free African countries. Two key steps are needed to make further progress in polio eradication: 1) addressing local barriers to interrupting transmission, and 2) using bivalent oral poliovirus vaccine (bOPV) broadly for WPV 1 and 3 in supplemental immunization activities (SIAs).

  19. The biological significance of brain barrier mechanisms

    DEFF Research Database (Denmark)

    Saunders, Norman R; Habgood, Mark D; Møllgård, Kjeld;

    2016-01-01

    cells, and tanycytes (specialized glial cells) in the circumventricular organs. In the ependyma lining the cerebral ventricles in the adult brain, the cells are joined by gap junctions, which are not restrictive for intercellular movement of molecules. But in the developing brain, the forerunners...... structures are physiological mechanisms as the cells of the interfaces contain various metabolic transporters and efflux pumps, often ATP-binding cassette (ABC) transporters, that provide an important component of the barrier functions by either preventing entry of or expelling numerous molecules including......Barrier mechanisms in the brain are important for its normal functioning and development. Stability of the brain's internal environment, particularly with respect to its ionic composition, is a prerequisite for the fundamental basis of its function, namely transmission of nerve impulses...

  20. Method of installing subsurface barrier

    Science.gov (United States)

    Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

    2007-10-09

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  1. Quasi-bound states, resonance tunnelling, and tunnelling times generated by twin symmetric barriers

    Indian Academy of Sciences (India)

    A Uma Maheswari; P Prema; S Mahadevan; C S Shastry

    2009-12-01

    In analogy with the definition of resonant or quasi-bound states used in three-dimensional quantal scattering, we define the quasi-bound states that occur in one-dimensional transmission generated by twin symmetric potential barriers and evaluate their energies and widths using two typical examples: (i) twin rectangular barrier and (ii) twin Gaussian-type barrier. The energies at which reflectionless transmission occurs correspond to these states and the widths of the transmission peaks are also the same as those of quasi-bound states. We compare the behaviour of the magnitude of wave functions of quasi-bound states with those for bound states and with the above-barrier state wave function. We deduce a Breit–Wigner-type resonance formula which neatly describes the variation of transmission coefficient as a function of energy at below-barrier energies. Similar formula with additional empirical term explains approximately the peaks of transmission coefficients at above-barrier energies as well. Further, we study the variation of tunnelling time as a function of energy and compare the same with transmission, reflection time and Breit–Wigner delay time around a quasi-bound state energy. We also find that tunnelling time is of the same order of magnitude as lifetime of the quasi-bound state, but somewhat larger.

  2. Double Barrier Resonant Tunneling in Spin-Orbit Coupled Bose—Einstein Condensates

    International Nuclear Information System (INIS)

    We study the double barrier tunneling properties of Dirac particles in spin-orbit coupled Bose—Einstein Condensates. The analytic expression of the transmission coefficient of Dirac particles penetrating into a double barrier is obtained. An interesting resonance tunneling phenomenon is discovered in the Klein block region which has been ignored before

  3. P-glycoprotein plays a major role in the efflux of fexofenadine in the small intestine and blood-brain barrier, but only a limited role in its biliary excretion.

    Science.gov (United States)

    Tahara, Harunobu; Kusuhara, Hiroyuki; Fuse, Eiichi; Sugiyama, Yuichi

    2005-07-01

    Fexofenadine is a selective, nonsedating H(1)-receptor antagonist approved for symptoms of allergic conditions, which is mainly excreted into feces via biliary excretion. The purpose of this study is to investigate its pharmacokinetics in mice and rats to determine the role of P-glycoprotein (P-gp) in its biliary excretion. In mice, biliary excretion clearance (17 ml/min/kg) accounted for almost 60% of the total body clearance (30 ml/min/kg). Comparing the pharmacokinetics after intravenous and oral administration indicated that the bioavailability of fexofenadine was at most 2% in mice. Knockout of Mdr1a/1b P-gp did not affect the biliary excretion clearance with regard to both plasma and liver concentrations, whereas the absence of P-gp caused a 6-fold increase in the plasma concentration after oral administration. In addition, the steady-state brain-to-plasma concentration ratio of fexofenadine was approximately 3-fold higher in Mdr1a/1b P-gp knockout mice than in wild-type mice. Together, these results show that P-glycoprotein plays an important role in efflux transport in the brain and small intestine but only a limited role in biliary excretion in mice. In addition, there was no difference in the biliary excretion between normal and hereditarily multidrug resistance-associated protein 2 (Mrp2)-deficient mutant rats (Eisai hyperbilirubinemic rats) and between wild-type and breast cancer resistance protein (Bcrp) knockout mice. These results suggest that the biliary excretion of fexofenadine is mediated by unknown transporters distinct from P-gp, Mrp2, and Bcrp.

  4. 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

  5. Watching Handball Transmissions

    DEFF Research Database (Denmark)

    Frandsen, Kirsten

    2010-01-01

    , 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...

  6. Barriers for the introduction of bioenergy in the Netherlands

    International Nuclear Information System (INIS)

    The use of biomass for energy in the Netherlands is still limited despite the political incentives to make bio-energy a major source of renewable energy. The hesitation of many stake-holders is due to the limited insight into the potential of biomass in the Netherlands and the presence of numerous other barriers. Availability of biomass, emission regulation and waste treatment regulations are considered important barriers. Analyses of their current state show that these barriers are broadly recognised and possibilities to decrease their impact are present. Some barriers with a minor influence so far will be of increasing importance and could be a threat to the development of bio-energy in future. These are the fast liberalising of the energy market and sustainable energy market, the competition with other renewables and the unclear status of the current technology available. Future research should focus on the possibilities to overcome these new barriers. 5 refs

  7. 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....... There is no single marker suitable for all purposes. A combination of different sized, visualizable dextrans and radiolabeled molecules currently seems to be the most appropriate approach for qualitative and quantitative assessment of barrier integrity....

  8. Barriers in Quantum Gravity

    OpenAIRE

    Ambjorn, Jan

    1994-01-01

    I discuss recent progress in our understanding of two barriers in quantum gravity: $c > 1$ in the case of 2d quantum gravity and $D > 2$ in the case of Euclidean Einstein-Hilbert gravity formulated in space-time dimensions $D >2$.

  9. Breaking Down Barriers.

    Science.gov (United States)

    Watkins, Beverly T.

    1994-01-01

    Faculty at 11 higher education institutions in California, New Mexico, Texas, and northern Mexico have been experimenting with computer conferencing on the BESTNET (Bilingual English-Spanish Telecommunications Network). The growing system is credited with creating an international student-faculty community that crosses cultural barriers for…

  10. Resonance-like tunneling across a barrier with adjacent wells

    Indian Academy of Sciences (India)

    S Mahadevan; P Prema; S K Agarwalla; B Sahu; C S Shastry

    2006-09-01

    We examine the behavior of transmission coefficient across the rectangular barrier when attractive potential well is present on one or both sides and also the same is studied for a smoother barrier with smooth adjacent wells having Woods–Saxon shape. We find that presence of well with suitable width and depth can substantially alter at energies below the barrier height leading to resonant-like structures. In a sense, this work is complementary to the resonant tunneling of particles across two rectangular barriers, which is being studied in detail in recent years with possible applications in mind. We interpret our results as due to resonant-like positive energy states generated by the adjacent wells. We describe in detail the possible potential application of these results in electronic devices using n-type oxygen-doped gallium arsenide and silicon dioxide. It is envisaged that these results will have applications in the design of tunneling devices.

  11. Barrier island arcs along abandoned Mississippi River deltas

    Science.gov (United States)

    Penland, S.; Suter, J.R.; Boyd, Ron

    1985-01-01

    Generation of transgressive barrier island arcs along the Mississippi River delta plain and preservation of barrier shoreline facies in their retreat paths on the inner shelf is controlled by: (1) shoreface translation; (2) age of the transgression; and (3) the thickness of the barrier island arc sediment package. Barrier island arcs experience an average relative sea level rise of 0.50-1.00 cm yr-1 and shoreface retreat rates range from 5-15 m yr-1. Young barrier island arc sediment packages (Isles Dernieres) are thin and have experienced limited landward retreat of the shoreface. Older barrier island arcs (Chandeleur Islands) are thicker and have experienced significant landward movement of the shoreface because of the greater time available for retreat. If the transgressed barrier shoreline sediment package lies above the advancing ravinement surface, the entire sequence is truncated. A thin reworked sand sheet marks the shoreface retreat path. The base of the transgressive sediment package can lie below the ravinement surface in older barrier shorelines. In this setting, the superstructure of the barrier shoreline is truncated, leaving the basal portion of the transgressive sequence preserved on the inner shelf. A variety of transgressive stratigraphic sequences from sand sheets to truncated barrier islands to sand-filled tidal inlet scars have been identified by high resolution seismic profiling across the shoreface retreat paths of Mississippi delta barrier island arcs. One of these examples, the Isles Dernieres, represents a recently detached barrier island arc in the early stages of transgression. An older example, the Chandeleur Islands, represents a barrier island arc experiencing long-term shoreface retreat. This paper describes the stratigraphic character and preserved transgressive facies for the Isles Dernieres and Chandeleur Islands. ?? 1985.

  12. Facilitating facial retinization through barrier improvement.

    Science.gov (United States)

    Draelos, Zoe Diana; Ertel, Keith D; Berge, Cynthia A

    2006-10-01

    The utility of topical tretinoin as a treatment for improving the appearance of photodamaged skin is limited by irritation that occurs during the early phases of facial retinization. The observed side effects are consistent with stratum corneum barrier compromise. This paired double-blinded study was conducted to determine if preconditioning the skin with a barrier-enhancing cosmetic facial moisturizer before beginning tretinoin therapy and continuing moisturizer application during therapy would mitigate these side effects. Women with facial photodamage were recruited and randomly assigned to apply one cosmetic moisturizer to one side of the face and the other cosmetic moisturizer to the other side of the face twice daily for 10 weeks. One moisturizer contained a mixture of vitamins (niacinamide, panthenol, and tocopheryl acetate) to enhance stratum corneum barrier function, and the other moisturizer contained similar moisturizing ingredients but no vitamins. Daily full-face treatment with tretinoin cream 0.025% commenced 2 weeks into the study. Subjects' facial skin condition was monitored via investigator assessments, instrumental measurements, and subject self-assessments. The results show that improving stratum corneum barrier function before beginning topical tretinoin therapy and continuing use of a barrier-enhancing cosmetic moisturizer during therapy facilitates the early phase of facial retinization and augments the treatment response. PMID:17121065

  13. Fundamental Limits of Ultrathin Metasurfaces

    CERN Document Server

    Arbabi, Amir

    2014-01-01

    We present universal theoretical limits on the operation and performance of non-magnetic passive ultrathin metasurfaces. In particular, we prove that their local transmission, reflection, and polarization conversion coefficients are confined to limited regions of the complex plane. As a result, full control over the phase of the light transmitted through such metasurfaces cannot be achieved if the polarization of the light is not to be affected at the same time. We also establish fundamental limits on the maximum polarization conversion efficiency of these metasurfaces, and show that they cannot achieve more than 25% polarization conversion efficiency in transmission.

  14. Observation of millimeter-wave oscillations from resonant tunneling diodes and some theoretical considerations of ultimate frequency limits

    Science.gov (United States)

    Sollner, T. C. L. G.; Brown, E. R.; Goodhue, W. D.; Le, H. Q.

    1987-01-01

    Recent observations of oscillation frequencies up to 56 GHz in resonant tunneling structures are discussed in relation to calculations by several authors of the ultimate frequency limits of these devices. It is found that calculations relying on the Wentzel-Kramers-Brillouin (WKB) approximation give limits well below the observed oscillation frequencies. Two other techniques for calculating the upper frequency limit were found to give more reasonable results. One method employs the solution of the time-dependent Schroedinger equation obtained by Kundrotas and Dargys (1986); the other uses the energy width of the transmission function for electrons through the double-barrier structure. This last technique is believed to be the most accurate since it is based on general results for the lifetime of any resonant state. It gives frequency limits on the order of 1 THz for two recently fabricated structures. It appears that the primary limitation of the oscillation frequency for double-barrier resonant-tunneling diodes is imposed by intrinsic device circuit parameters and by the transit time of the depletion layer rather than by time delays encountered in the double-barrier region.

  15. Scattering of massless Dirac particles by oscillating barriers in one dimension

    Energy Technology Data Exchange (ETDEWEB)

    González-Santander, C. [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Domínguez-Adame, F., E-mail: adame@ucm.es [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Fuentevilla, C.H.; Diez, E. [Laboratorio de Bajas Temperaturas, Universidad de Salamanca, E-37008 Salamanca (Spain)

    2014-02-01

    We study the scattering of massless Dirac particles by oscillating barriers in one dimension. Using the Floquet theory, we find the exact scattering amplitudes for time-harmonic barriers of arbitrary shape. In all cases the scattering amplitudes are found to be independent of the energy of the incoming particle and the transmission coefficient is unity. This is a manifestation of the Klein tunneling in time-harmonic potentials. Remarkably, the transmission amplitudes for arbitrary sharply-peaked potentials also become independent of the driving frequency. Conditions for which barriers of finite width can be replaced by sharply-peaked potentials are discussed.

  16. 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.

  17. Plasmodium vivax Transmission in Africa.

    Science.gov (United States)

    Howes, Rosalind E; Reiner, Robert C; Battle, Katherine E; Longbottom, Joshua; Mappin, Bonnie; Ordanovich, Dariya; Tatem, Andrew J; Drakeley, Chris; Gething, Peter W; Zimmerman, Peter A; Smith, David L; Hay, Simon I

    2015-11-01

    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 significance of Pv, as well

  18. 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

  19. Geophysical characterization of subsurface barriers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Geophysical characterization of subsurface barriers

    International Nuclear Information System (INIS)

    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

  1. Bordetella pertussis transmission.

    Science.gov (United States)

    Trainor, Elizabeth A; Nicholson, Tracy L; Merkel, Tod J

    2015-11-01

    Bordetella pertussis and B. bronchiseptica are Gram-negative bacterial respiratory pathogens. Bordetella pertussis is the causative agent of whooping cough and is considered a human-adapted variant of B. bronchiseptica. Bordetella pertussis and B. bronchiseptica share mechanisms of pathogenesis and are genetically closely related. However, despite the close genetic relatedness, these Bordetella species differ in several classic fundamental aspects of bacterial pathogens such as host range, pathologies and persistence. The development of the baboon model for the study of B. pertussis transmission, along with the development of the swine and mouse model for the study of B. bronchiseptica, has enabled the investigation of different aspects of transmission including the route, attack rate, role of bacterial and host factors, and the impact of vaccination on transmission. This review will focus on B. pertussis transmission and how animal models of B. pertussis transmission and transmission models using the closely related B. bronchiseptica have increased our understanding of B. pertussis transmission.

  2. New Comparison of HVDC and HVAC Transmission system

    Directory of Open Access Journals (Sweden)

    Vahid Behravesh

    2012-06-01

    Full Text Available Alternating current (AC is the main driving force in the industries and residential areas, but for the long transmission line (more than 400 miles AC transmission is more expensive than that of direct current (DC. Technically, AC transmission line control is more complicated because of the frequency. DC transmission does not have these limitations, which has led to build long HVDC transmission lines over the last 40 years. HVDC technology made possible to transfer bulk power over long distances. This paper presents a comparative evaluation of HVDC and HVAC transmission systems .

  3. Adiabatic Heavy Ion Fusion Potentials for Fusion at Deep Sub-barrier Energies

    CERN Document Server

    Sastry, S V S; Mohanty, A K; Saxena, A

    2003-01-01

    The fusion cross sections from well above barrier to extreme sub-barrier energies have been analysed using the energy (E) and angular momentum (L) dependent barrier penetration model ({\\small{ELDBPM}}). From this analysis, the adiabatic limits of fusion barriers have been determined for a wide range of heavy ion systems. The empirical prescription of Wilzynska and Wilzynski has been used with modified radius parameter and surface tension coefficient values consistent with the parameterization of the nuclear masses. The adiabatic fusion barriers calculated from this prescription are in good agreement with the adiabatic barriers deduced from {\\small{ELDBPM}} fits to fusion data. The nuclear potential diffuseness is larger at adiabatic limit, resulting in a lower $\\hbar\\omega$ leading to increase of "logarithmic slope" observed at energies well below the barrier. The effective fusion barrier radius and curvature values are anomalously smaller than the predictions of known empirical prescriptions. A detailed comp...

  4. Natural Barriers of the Geosphere at Yucca Mountain, Nevada

    Science.gov (United States)

    Arlt, H.; Kotra, J.; Mohanty, S.; Winterle, J.

    2005-05-01

    Geological repositories designed to isolate high-level radioactive waste need natural and engineered barriers that prevent or slow the release of radioactive elements into the accessible environment to acceptable regulatory limits. Under the U.S. Nuclear Regulatory Commission's (NRC's) regulations, a barrier is any material, structure, or feature that prevents or substantially reduces the rate of movement of water or radionuclides from the repository to the accessible environment. In 1982, Congress passed the Nuclear Waste Policy Act which directed the NRC to include multiple barriers in regulating geologic disposal of high-level radioactive waste. Accordingly, as provided in 10 CFR Part 63, the NRC's regulations for Yucca Mountain require a repository to include multiple barriers to ensure the system is robust and not wholly dependent on any single barrier. Any potential license application to construct a repository at Yucca Mountain must identify the multiple barriers (both natural and engineered), describe the capabilities of each barrier, and provide the technical bases for the capabilities of the barriers. The NRC believes that understanding the capability of the repository's component barriers improves understanding of the overall system. The objective of this paper is to discuss potential natural barriers of the geosphere at Yucca Mountain and describe the NRC regulatory requirements for such barriers. To better understand the natural barriers of the geosphere, it helps to divide the barriers into groups of features and their associated processes. Natural barriers, i.e., barriers not constructed by man, ideally include processes that delay the transport of radionuclides from reaching the accessible environment or limit the amount of water that can seep from a ground surface to the depth of an underground repository. Natural barriers at Yucca Mountain may include: topographic influences on precipitation runoff; soil and plants influences on evaporation and

  5. Minutes of Fish Barrier Workshop

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Minutes of Fish Barrier Workshop held 27 May 2009 at DOC Waikato Area Office. Lists attendees and highlights topics to be covered in Fish Barrier Workshop.

  6. Current-voltage relation for thin tunnel barriers: Parabolic barrier model

    DEFF Research Database (Denmark)

    Hansen, Kim; Brandbyge, Mads

    2004-01-01

    We derive a simple analytic result for the current-voltage curve for tunneling of electrons through a thin uniform insulating layer modeled by a parabolic barrier. Our model, which goes beyond the Wentzel–Kramers–Brillouin approximation, is applicable also in the limit of highly transparant...

  7. Analysis, Design and Application of Continuously Variable Transmission (CVT)

    OpenAIRE

    Vishnu Seelan

    2015-01-01

    Continuously Variable Transmission (CVT) offers a continuum of gear ratios between desired limits. This allows the engine to operate more time in the optimum range. In contrast, traditional automatic and manual transmissions have several fixed transmission ratios forcing the engine to operate outside the optimum range. The need for a transmission system and the working principle of CVT has been discussed in depth. An attempt has been made to understand the contribution of Hydrauli...

  8. Where is the Limit? Barriers of Theories - Organisations without Boundaries

    OpenAIRE

    István Szintay

    2012-01-01

    The paper addresses the issue of inter-organisational cooperation. Networks change economic relations fundamentally; however, theory has devoted so far relatively little attention to this development of significance in economic history. It can be attributed to the fact that many evaluate the transformation of large vertical concerns into loose networks as unambiguously as gaining ground by the market against hierarchies. Although there is no doubt that the transformation of large organisation...

  9. Electron Transport in Graphene-Based Double-Barrier Structure under a Time Periodic Field

    Institute of Scientific and Technical Information of China (English)

    LU Wei-Tao; WANG Shun-Jin

    2011-01-01

    The transport property of electron through graphene-based double-barrier under a time periodic field is investigated. We study the influence of the system parameters and external field strength on the transmission probability.The results show that transmission exhibits various kinds of behavior with the change of parameters due to its angular anisotropy. One could control the values of transmission and conductivity as well as their distribution in each band by tuning the parameters.

  10. Realization of a double-barrier resonant tunneling diode for cavity polaritons.

    Science.gov (United States)

    Nguyen, H S; Vishnevsky, D; Sturm, C; Tanese, D; Solnyshkov, D; Galopin, E; Lemaître, A; Sagnes, I; Amo, A; Malpuech, G; Bloch, J

    2013-06-01

    We report on the realization of a double-barrier resonant tunneling diode for cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp transmission resonances are demonstrated when sending a polariton flow onto the device. We show that a nonresonant beam can be used as an optical gate and can control the device transmission. Finally, we evidence distortion of the transmission profile when going to the high-density regime, signature of polariton-polariton interactions. PMID:25167519

  11. Realization of a Double-Barrier Resonant Tunneling Diode for Cavity Polaritons

    OpenAIRE

    Nguyen, Hai Son; Vishnevsky, Dmitry; Sturm, Chris; Tanese, Dimitrii; Solnyshkov, Dmitry; Galopin, Elisabeth; Lemaître, Aristide; Sagnes, Isabelle; Amo, Alberto; Malpuech, Guillaume; Bloch, Jacqueline

    2013-01-01

    We report on the realization of a double barrier resonant tunneling diode for cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp transmission resonances are demonstrated when sending a polariton flow onto the device. We use a non-resonant beam can be used as an optical gate and control the device transmission. Finally we evidence distortion of the transmission profile when going to the high density regime, signature of polariton-polariton interactions.

  12. Realization of a Double-Barrier Resonant Tunneling Diode for Cavity Polaritons

    Science.gov (United States)

    Nguyen, H. S.; Vishnevsky, D.; Sturm, C.; Tanese, D.; Solnyshkov, D.; Galopin, E.; Lemaître, A.; Sagnes, I.; Amo, A.; Malpuech, G.; Bloch, J.

    2013-06-01

    We report on the realization of a double-barrier resonant tunneling diode for cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp transmission resonances are demonstrated when sending a polariton flow onto the device. We show that a nonresonant beam can be used as an optical gate and can control the device transmission. Finally, we evidence distortion of the transmission profile when going to the high-density regime, signature of polariton-polariton interactions.

  13. Transmission Scintiphotography and its Applications

    International Nuclear Information System (INIS)

    Clear transmission pictures have been obtained of the heart, diaphragm, trachea, and the lungs in both PA and lateral projections, using the scintillation camera and a radioactive source on the opposite side of the patient. Gas within the stomach and bowel is visualized, and contrast media is readily seen in the intestine. Transmission scintiphotos are of use in the interpretation of the conventional emission scintiphotos. For example, transmission pictures define the extent of the lung so that lung perfusion studies can be interpreted properly. They show the position of the diaphragm in liver studies so that space-occupying lesions between the liver and diaphragm can be detected. They are also useful in positioning the heart and lung fields for dynamic tracer studies. tracer studies. The use of transmission scanning with a rectilinear scanner as a means of improving the interpretation of radionuclide emission scans has been reported previously by Kuhl et al. and it has also been used by Anger in the Whole Body Scanner Mark II. To take transmission images with the scintillation camera, a conventional multichannel collimator is placed on the camera and a radiocactive disc source 11 in. in diameter is placed underneath the patient. A second multichannel collimator is placed on top of the source to reduce the radiation dose to the patient. It also reduces the amount of scattered radiation that appears on the pictures. If the disc source contains about 10-20 mCi of 99mTc, transmission pictures can be taken in 1-2 min. The patient receives less than 1 mR/h to a limited area of the body and virtually no irradiation elsewhere. The 140-keV gamma rays from technetium have very little selective absorption in bone, compared to Iower-energy gamma rays and X-rays. They are scattered by all tissues, and therefore are useful for imaging air spaces within the body such as the lungs. Defects in these air spaces, such as large solid space- occupying lesions in the lungs, can also be

  14. Sonic Crystal Noise Barriers

    OpenAIRE

    Chong, Yung

    2012-01-01

    An alternative road traffic noise barrier using an array of periodically arranged vertical cylinders known as a Sonic Crystal (SC) is investigated. As a result of multiple (Bragg) scattering, SCs exhibit a selective sound attenuation in frequency bands called band gaps or stop bands related to the spacing and size of the cylinders. Theoretical studies using Plane Wave Expansion (PWE), Multiple Scattering Theory (MST) and Finite Element Method (FEM) have enabled study of the performance of SC ...

  15. PHARMACOVIGILANCE: BARRIERS AND CHALLENGES

    OpenAIRE

    Varma, S. K.; RAPELLIWAR A; S. Sutradhar; THAWARE P; Misra, A. K.

    2013-01-01

    Pharmacovigilance is a new discipline which deals with adverse drug or any drug related problems. Pharmacovigilance programme was not bed of roses but its path is laid with challenges and barriers. It is facing obstacles from deficiency from professional health personal to web-based sale of drugs, counterfeit drug to self-medication, etc. It is an integral part of the health sector and identification and reporting of adverse drug effects will have a positive impact on the public health. Impro...

  16. Thermal barrier coating materials

    Directory of Open Access Journals (Sweden)

    David R. Clarke

    2005-06-01

    Full Text Available Improved thermal barrier coatings (TBCs will enable future gas turbines to operate at higher gas temperatures. Considerable effort is being invested, therefore, in identifying new materials with even better performance than the current industry standard, yttria-stabilized zirconia (YSZ. We review recent progress and suggest that an integrated strategy of experiment, intuitive arguments based on crystallography, and simulation may lead most rapidly to the development of new TBC materials.

  17. Resonant tunnelling of electrons in multi-step single-barrier heterostructures

    Institute of Scientific and Technical Information of China (English)

    Wang Chang; Zhang Yong-Hua

    2006-01-01

    We have studied the quantum transport of electrons in a three-step single-barrier A1GaAs heterostructure under electric field. Using the quantum transmitting boundary method and Tsu-Esaki approach, we have calculated the transmission coefficient and current-voltage characteristic. The difference of the effective mass among the three barriers is taken into account. Effects of the barrier width on transmission coefficient and peak-to-valley current ratios are examined. The largest peak-to-valley current ratio is obtained when the ratio of widths of the left, middle, and right barrier is fixed at 4:2:1. The calculated results may be helpful for designing devices based on three-step barrier heterostructures.

  18. Fractional extension of Kramers rate and barrier escaping from metastable potential well

    CERN Document Server

    Wang, Chun-Yang

    2015-01-01

    The reactive process of barrier escaping from the metastable potential well is studied together with the extension of Kramers' rate formula to the fractional case. Characteristic quantities are computed for an thimbleful of insight into the near barrier escaping and recrossing dynamics. Where the stationary transmission coefficient is revealed to be larger than the usual cases which implies less barrier recrossing. And the non-monotonic varying of it reveals a close dependence to the fractional exponent $\\alpha$. In most cases, the near barrier behavior of the escaping dynamics is equivalent to the diffusion in the two-dimensional non-Ohmic damping system.

  19. Simulation of double barrier resonant tunneling diodes

    OpenAIRE

    Porter, Roy M.

    1996-01-01

    The double barrier resonant tunneling diode (DBRTD) is one of several devices currently being considered by the semiconductor industry as a replacement for conventional very large scale integrated (VLSI) circuit technology when the latter reaches its currently perceived scaling limits. The DBRTD was one of the first and remains one of the most promising devices to exhibit a room temperature negative differential resistance (NDR); this non-linear device characteristic has innovative circuit ap...

  20. The monetary transmission mechanism

    OpenAIRE

    Peter N. Ireland

    2005-01-01

    The monetary transmission mechanism describes how policy-induced changes in the nominal money stock or the short-term nominal interest rate impact on real variables such as aggregate output and employment. Specific channels of monetary transmission operate through the effects that monetary policy has on interest rates, exchange rates, equity and real estate prices, bank lending, and firm balance sheets. Recent research on the transmission mechanism seeks to understand how these channels work ...

  1. Series Transmission Line Transformer

    Science.gov (United States)

    Buckles, Robert A.; Booth, Rex; Yen, Boris T.

    2004-06-29

    A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

  2. Locally addressable tunnel barriers within a carbon nanotube

    DEFF Research Database (Denmark)

    Biercuk, M.; Mason, N.; Chow, J.;

    2003-01-01

    We report the realization and characterization of independently controllable tunnel barriers within a carbon nanotube. The nanotubes are mechanically bent or kinked using an atomic force microscope, and top gates are subsequently placed near each kink. Transport measurements indicate that the kinks...... form gate-controlled tunnel barriers, and that gates placed away from the kinks have little or no effect on conductance. The overall conductance of the nanotube can be controlled by tuning the transmissions of either the kinks or the metal-nanotube contacts....

  3. Structured noise induced non-recross barrier escaping

    CERN Document Server

    Wang, Chun-Yang

    2015-01-01

    The time-dependent barrier passage of a particle driven by the structured noise is studied in the field of a metastable potential. Quantities such as the probability of passing over the saddle point and transmission coefficient of the escaping rate are calculated for a thimbleful of insight into the diffusion dynamical properties. Results show that the barrier recrossing behavior is greatly reduced by the structured noisy environment. Particles diffusion in such an dissipative environment tends to successfully escape from the potential well without any embarrassments.

  4. Scattering of topological solitons on holes and barriers

    CERN Document Server

    Piette, B; Brand, J; Piette, Bernard; Brand, Joachim

    2005-01-01

    We study the scattering properties of topological solitons on obstructions in the form of holes and barriers. We use the 'new baby Skyrme' model in (2+1) dimensions and we model the obstructions by making the coefficient of the baby skyrme model potential - position dependent. We find that that the barrier leads to the repulsion of the solitons (for low velocities) or their complete transmission (at higher velocities) with the process being essentially elastic. The hole case is different; for small velocities the solitons are trapped while at higher velocities they are transmitted with a loss of energy. We present some comments explaining the observed behaviour.

  5. Scattering of topological solitons on holes and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Piette, Bernard [Department of Mathematical Sciences, University of Durham, Science Laboratories, South Road, Durham DH1 3LE (United Kingdom); Zakrzewski, W J [Department of Mathematical Sciences, University of Durham, Science Laboratories, South Road, Durham DH1 3LE (United Kingdom); Brand, Joachim [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)

    2005-12-02

    We study the scattering properties of topological solitons on obstructions in the form of holes and barriers. We use the 'new baby Skyrme' model in (2 + 1) dimensions and we model the obstructions by making the coefficient of the baby Skyrme model potential-position dependent. We find that the barrier leads to the repulsion of the solitons (for low velocities) or their complete transmission (at higher velocities) with the process being essentially elastic. The hole case is different; for small velocities the solitons are trapped while at higher velocities they are transmitted with a loss of energy. We present some comments explaining the observed behaviour.

  6. Exploring the multi-humped fission barrier of 238U via sub-barrier photofission

    CERN Document Server

    Csige, L; Glodariu, T; Gulyás, J; Günther, M M; Habs, D; Karwowski, H J; Krasznahorkay, A; Rich, G C; Sin, M; Stroe, L; Tesileanu, O; Thirolf, P G

    2013-01-01

    The photofission cross-section of 238U was measured at sub-barrier energies as a function of the gamma-ray energy using, for the first time, a monochromatic, high-brilliance, Compton-backscattered gamma-ray beam. The experiment was performed at the High Intensity gamma-ray Source (HIgS) facility at beam energies between E=4.7 MeV and 6.0 MeV and with ~3% energy resolution. Indications of transmission resonances have been observed at gamma-ray beam energies of E=5.1 MeV and 5.6 MeV with moderate amplitudes. The triple-humped fission barrier parameters of 238U have been determined by fitting EMPIRE-3.1 nuclear reaction code calculations to the experimental photofission cross section.

  7. Exploring the multihumped fission barrier of 238U via sub-barrier photofission

    Science.gov (United States)

    Csige, L.; Filipescu, D. M.; Glodariu, T.; Gulyás, J.; Günther, M. M.; Habs, D.; Karwowski, H. J.; Krasznahorkay, A.; Rich, G. C.; Sin, M.; Stroe, L.; Tesileanu, O.; Thirolf, P. G.

    2013-04-01

    The photofission cross section of 238U was measured at sub-barrier energies as a function of the γ-ray energy using a monochromatic, high-brilliance, Compton-backscattered γ-ray beam. The experiment was performed at the High Intensity γ-ray Source (HIγS) facility at beam energies between Eγ=4.7 MeV and 6.0 MeV and with ˜3% energy resolution. Indications of transmission resonances have been observed at γ-ray beam energies of Eγ=5.1 MeV and 5.6 MeV with moderate amplitudes. The triple-humped fission barrier parameters of 238U have been determined by fitting empire-3.1 nuclear reaction code calculations to the experimental photofission cross section.

  8. On limit and limit setting.

    Science.gov (United States)

    Gorney, J E

    1994-01-01

    This article investigates the role of limit and limit setting within the psychoanalytic situation. Limit is understood to be a boundary between self and others, established as an interactional dimension of experience. Disorders of limit are here understood within the context of Winnicott's conception of the "anti-social tendency." Limit setting is proposed as a necessary and authentic response to the patient's acting out via holding and empathic responsiveness, viewed here as a form of boundary delineation. It is proposed that the patient attempts to repair his or her boundary problem through a seeking of secure limits within the analyst. The setting of secure and appropriate limits must arise from a working through of the analyst's own countertransference response to the patient. It is critical that this response be evoked by, and arise from, the immediate therapeutic interaction so that the patient can experience limit setting as simultaneously personal and authentic. PMID:7972580

  9. Barriers for recess physical activity

    DEFF Research Database (Denmark)

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

    2014-01-01

    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......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...... and girls identified the same barriers, there were both inter- and intra-gender differences in the perception of these barriers. Weather was a barrier for all children, apart from the most active boys. Conflicts were perceived as a barrier particularly by those boys who played ballgames. Girls said...

  10. 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.

  11. Quench limits

    International Nuclear Information System (INIS)

    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)

  12. 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.

  13. [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

  14. Technical barrier challenges

    Institute of Scientific and Technical Information of China (English)

    李思佳

    2014-01-01

    according to a famouse report,the foreign Technical Barriers to Trade(TBT)have some effects on the exports of the People’s Republic of China.Major findings are as follows:(1)TBT makes it more difficult for China to export;(2)TBT increases the costs of Chinese export commodities;(3)TBT causes friction and confilicts in the international trade;(4)SOME developed countries have moved their phase-outs to China and other developing countries,which have become victims of TBT.

  15. Technical barrier challenges

    Institute of Scientific and Technical Information of China (English)

    李思佳

    2014-01-01

    according to a famouse report,the foreign Technical Barriers to Trade(TBT) have some effects on the exports of the People's Republic of China.Major findings are as follows:(1)TBT makes it more difficult for China to export;(2)TBT increases the costs of Chinese export commodities;(3)TBT causes friction and confilicts in the international trade;(4)SOME developed countries have moved their phase-outs to China and other developing countries,which have become victims of TBT.

  16. Tearing Down Disciplinary Barriers

    Science.gov (United States)

    Roederer, Juan G.

    1988-05-01

    Profesor Hannes Alfvén's life-long battle against scientific narrow-mindedness and parochial approaches to the solution of scientific problems is well known and deeply appreciated by this author. In this article the new interdisciplinary trends in science are critically examined and the psychological impacts of crumbling disciplinary barriers on the participating scientists are analyzed. Several examples of interdisciplinary research programs are discussed and some thoughts on the structural reform of scientific organizations, agencies, and universities needed to face these trends are given.

  17. Transmission of Atypical Bovine Prions to Mice Transgenic for Human Prion Protein

    OpenAIRE

    Béringue, Vincent; Herzog, Laëtitia; Reine, Fabienne; Le Dur, Annick; Casalone, Cristina; Vilotte, Jean-Luc; Laude, Hubert

    2008-01-01

    To assess risk for cattle-to-human transmission of prions that cause uncommon forms of bovine spongiform encephalopathy (BSE), we inoculated mice expressing human PrP Met129 with field isolates. Unlike classical BSE agent, L-type prions appeared to propagate in these mice with no obvious transmission barrier. H-type prions failed to infect the mice.

  18. Investigation of Transmission Resonances with Specific Properties in Rectangular Semiconductor Quantum Wells

    Science.gov (United States)

    Niketic, Nemanja; Milanovic, Vitomir; Radovanovic, Jelena

    2012-01-01

    In this paper we provide a detailed analysis of the energy position and type of transmission maxima in rectangular quantum wells (QWs), taking into consideration the difference of electron effective masses in the barrier and well layers. Particular attention is given to transmission maxima that are less than unity and the implications of effective…

  19. Data Transmission Concepts.

    Science.gov (United States)

    Christenson, Chris

    1995-01-01

    Introduces some basic concepts related to the transmission of data from a computer to its peripherals to help distance educators make decisions regarding computer equipment purchases for their institutions. The following data transmission concepts are described: cables, serial and parallel, synchronous and asynchronous, bandwidth, and analog and…

  20. 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 t...

  1. 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.

  2. A permeability barrier surrounds taste buds in lingual epithelia.

    Science.gov (United States)

    Dando, Robin; Pereira, Elizabeth; Kurian, Mani; Barro-Soria, Rene; Chaudhari, Nirupa; Roper, Stephen D

    2015-01-01

    Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003-1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.

  3. Review of electromagnetic induction for mapping barrier island framework geology

    Science.gov (United States)

    Weymer, Bradley A.; Everett, Mark E.; de Smet, Timothy S.; Houser, Chris

    2015-05-01

    The geologic framework controls on modern barrier island transgression and the relationship of these controls to subsurface structure, hydrology and island geomorphology are not well understood. Recent evidence suggests that alongshore variations in pre-Holocene geology of barrier islands modify nearshore hydrodynamic processes and sediment transport, ultimately affecting how barrier islands will respond to relative sea-level rise. Explorations of Holocene barrier island geology are usually based on cores to supplement bathymetric, onshore/offshore seismic and/or ground-penetrating radar (GPR) surveys. The advantages and limitations of these methods with respect to barrier island investigations are briefly described in this review. Alternative near-surface geophysical methods including electromagnetic induction (EMI) sensors are increasingly being used for coastal research because they are non-invasive, provide continuous subsurface information across a variety of sub-environments, and are capable of characterizing large areas in a short time. Although these EMI sensors have shown promise in coastal applications, a number of issues primarily related to subsurface hydrology need to be addressed to fully assess the limitations of this technique. This paper reviews the theory, methodology and applications of EMI in support of geologic framework studies with particular reference to barrier islands. Resolution of these issues will allow EMI sensors to complement and offer significant advantages over traditional methods in support of an improved understanding of large-scale barrier island evolution.

  4. Dose limits

    International Nuclear Information System (INIS)

    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

  5. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  6. Barriers to entry : abolishing the barriers to understanding

    OpenAIRE

    Keppler, Jan Horst

    2009-01-01

    BARRIERS TO ENTRY: ABOLISHING THE BARRIERS TO UNDERSTANDING by Jan-Horst Keppler Professor of economics Université Paris – Dauphine, LEDa, and Université Paris I Panthéon-Sorbonne, PHARE Port.: (+33 6) 77 81 37 46; Email: . Abstract The concept of a barrier to entry has been discussed least since Bain (1956) with important contributions by Spence (1977), Dixit (1980) or Milgrom and Roberts (1982). The more recent discussion is synth...

  7. Enhanced Plasmonic Light Absorption for Silicon Schottky-Barrier Photodetectors

    DEFF Research Database (Denmark)

    Hashemi, Mahdieh; Farzad, Mahmood Hosseini; Mortensen, N. Asger;

    2013-01-01

    Quantum efficiency of the silicon Schottky-barrier photodetector is limited by the weak interaction between the photons and electrons in the metal. By engineering the metal surfaces, metallic groove structures are proposed to achieve strong light absorption in the metal, where most of the energy...... is transferred into hot carriers near the Schottky barrier. The proposed broadband photodetector with a bi-grating metallic structure on the silicon substrate enables to absorb 76 % of the infrared light in the metal with a 200-nm bandwidth, while staying insensitive to the incident angle. These results pave...... a new promising way to attain high quantum efficiency silicon Schottky-barrier photodetectors....

  8. Genetic Barriers to Resistance and Impact on Clinical Response

    Directory of Open Access Journals (Sweden)

    Luber Andrew D

    2005-07-01

    Full Text Available Abstract The development of drug resistance and cross-resistance continues to pose a challenge to successful long-term antiretroviral therapy despite the availability of new antiretroviral agents. The genetic barrier to resistance of a regimen does not directly correlate with its effectiveness. For some regimens with a low genetic barrier to resistance, however, the emergence of only 1 or 2 key resistance mutations may confer drug resistance not only to that regimen but also to other agents, thereby limiting subsequent treatment options. In addition to the genetic barrier to resistance, factors such as efficacy, safety, tolerability, convenience, and adherence must be considered when choosing a regimen.

  9. Barriers associated with reduced physical activity in COPD patients*

    OpenAIRE

    Priscila Batista Amorim; Rafael Stelmach; Celso Ricardo Fernandes de Carvalho; Frederico Leon Arrabal Fernandes; Regina Maria de Carvalho-Pinto; Alberto Cukier

    2014-01-01

    OBJECTIVE: To evaluate the ability of COPD patients to perform activities of daily living (ADL); to identify barriers that prevent these individuals from performing ADL; and to correlate those barriers with dyspnea severity, six-minute walk test (6MWT), and an ADL limitation score. METHODS: In COPD patients and healthy, age-matched controls, the number of steps, the distance walked, and walking time were recorded with a triaxial accelerometer, for seven consecutive days. A questionnaire regar...

  10. Isolation gowns in health care settings: Laboratory studies, regulations and standards, and potential barriers of gown selection and use.

    Science.gov (United States)

    Kilinc Balci, F Selcen

    2016-01-01

    Although they play an important role in infection prevention and control, textile materials and personal protective equipment (PPE) used in health care settings are known to be one of the sources of cross-infection. Gowns are recommended to prevent transmission of infectious diseases in certain settings; however, laboratory and field studies have produced mixed results of their efficacy. PPE used in health care is regulated as either class I (low risk) or class II (intermediate risk) devices in the United States. Many organizations have published guidelines for the use of PPE, including isolation gowns, in health care settings. In addition, the Association for the Advancement of Medical Instrumentation published a guidance document on the selection of gowns and a classification standard on liquid barrier performance for both surgical and isolation gowns. However, there is currently no existing standard specific to isolation gowns that considers not only the barrier resistance but also a wide array of end user desired attributes. As a result, infection preventionists and purchasing agents face several difficulties in the selection process, and end users have limited or no information on the levels of protection provided by isolation gowns. Lack of knowledge about the performance of protective clothing used in health care became more apparent during the 2014 Ebola epidemic. This article reviews laboratory studies, regulations, guidelines and standards pertaining to isolation gowns, characterization problems, and other potential barriers of isolation gown selection and use. PMID:26391468

  11. Synthetic Eelgrass Oil Barrier

    Science.gov (United States)

    Curtis, T. G.

    2013-05-01

    Although surviving in situ micro-organisms eventually consume spilled oil, extensive inundation of shore biota by oil requires cleanup to enable ecological recovery within normal time scales. Although effective in calm seas and quiet waters, oil is advected over and under conventional curtain oil booms by wave actions and currents when seas are running. Most sorbent booms are not reusable, and are usually disposed of in landfills, creating excessive waste. A new concept is proposed for a floating oil barrier, to be positioned off vulnerable coasts, to interdict, contain, and sequester spilled oil, which can then be recovered and the barrier reused. While conventional oil boom designs rely principally on the immiscibility of oil in water and its relative buoyancy, the new concept barrier avoids the pitfalls of the former by taking advantage of the synergistic benefits of numerous fluid and material properties, including: density, buoyancy, elasticity, polarity, and surface area to volume ratio. Modeled after Zostera marina, commonly called eelgrass, the new barrier, referred to as synthetic eelgrass (SE), behaves analogously. Eelgrass has very long narrow, ribbon-like, leaves which support periphyton, a complex matrix of algae and heterotrophic microbes, which position themselves there to extract nutrients from the seawater flowing past them. In an analogous fashion, oil on, or in, seawater, which comes in contact with SE, is adsorbed on the surface and sequestered there. Secured to the bottom, in shoal waters, SE rises to the surface, and, if the tide is low enough, floats on the sea surface down wind, or down current to snare floating oil. The leaves of SE, called filaments, consist of intrinsically buoyant strips of ethylene methyl acrylate, aka EMA. EMA, made of long chain, saturated, hydrocarbon molecules with nearly homogeneous electron charge distributions, is a non-polar material which is oleophilic and hydrophobic. Oil must be in close proximity to the

  12. EM transmission-line metamaterials

    Directory of Open Access Journals (Sweden)

    George V. Eleftheriades

    2009-03-01

    Full Text Available Metamaterials are understood to be artificially engineered materials that exhibit unusual or difficult to obtain electromagnetic (EM properties. Such properties would include negative or low values of permittivity, permeability and index of refraction. In this article, we review the fundamentals of metamaterials with emphasis on negative-refractive-index ones, which are synthesized using loaded transmission lines. A number of applications of such metamaterials are discussed, including peculiar lenses that can overcome the diffraction limit and small antennas for emerging wireless communication applications.

  13. 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

  14. 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

  15. Barriers to antenatal syphilis screening in Burkina Faso

    OpenAIRE

    Bocoum, Fadima Yaya; Kouanda, Seni; Zarowsky, Christina

    2014-01-01

    Introduction Despite advances in treatment and management, syphilis remains a major public health problem in Burkina Faso. Syphilis in pregnancy poses major health risks for the mother and the fetus and also increases the risk for HIV transmission. Despite its potential benefits, antenatal syphilis screening is often poorly implemented in many sub-Saharan African countries. The purpose of the study is to identify and understand barriers affecting health system performance for syphilis screeni...

  16. Genetic control of horizontal virus transmission in the chestnut blight fungus, Cryphonectria parasitica.

    OpenAIRE

    Cortesi, P; McCulloch, C.E.; Song, H; H. Lin; Milgroom, M G

    2001-01-01

    Vegetative incompatibility in fungi has long been known to reduce the transmission of viruses between individuals, but the barrier to transmission is incomplete. In replicated laboratory assays, we showed conclusively that the transmission of viruses between individuals of the chestnut blight fungus Cryphonectria parasitica is controlled primarily by vegetative incompatibility (vic) genes. By replicating vic genotypes in independent fungal isolates, we quantified the effect of heteroallelism ...

  17. Phase stability of thermal barrier oxides: a comparative study of Y and Yb additions

    Energy Technology Data Exchange (ETDEWEB)

    Cairney, J.M. [The Australian Key Centre for Microscopy and Microanalysis, Sydney (Australia); Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany); Rebollo, N.R.; Levi, C.G. [California Univ., Santa Barbara, CA (United States). Materials Dept.; Ruehle, M. [Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany)

    2007-12-15

    The maximum operating temperature of conventional thermal barrier coatings based on yttria-stabilized zirconia is ultimately limited by de-stabilization of the 'non-transformable' t' phase, rendering it susceptible to the monoclinic transformation upon cooling. Investigations into alternative thermal barrier oxide compositions suggest that Yb offers superior t' stability compared with Y, Sc and larger rare earth cations at the same concentration. The present study sheds light on this behavior by comparing the microstructure evolution of specimens with 7.6 and 11.4% MO{sub 1.5} (M = Y or Yb) heat treated at 1450 C for times up to 512 h. X-ray diffractometry and transmission electron microscopy revealed that the onset of partitioning occurs at short times but then the compositions of the phases evolve slowly over time until sufficient stabilizer is depleted from the t' phase to render it transformable. Substitution of Yb for Y delays the onset of monoclinic formation. Differences in the transformation behavior of the Y and Yb rich phases on cooling provide new insight and suggest refinements to the current thermodynamic models for the binary ZrO{sub 2}-MO{sub 1.5} systems are needed. (orig.)

  18. 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.

  19. AIDS, STDs encourage use of barrier methods.

    Science.gov (United States)

    Herndon, N

    1993-08-01

    Condom use in the Dominican Republic is being promoted, in part due to the spread of AIDS and sexually transmitted diseases (STDs). 90% of the married women using contraception prefer sterilization, oral contraceptives, IUDs, subdermal implants, or injectables. Barrier methods have never been very popular (5%). Cultural bias may account for some of the avoidance of barrier methods. Men complain about the effects on pleasure and spontaneity. There is uncertainty about what emphasis family planning (FP) programs should place on STD prevention; STD services would make FP popular but also could strain existing services and financial resources. Educational efforts to encourage barrier use are hampered by the lack of access to indoor plumbing, since most barrier methods are messy. Cost may be another limitation on widespread use. PROFAMILIA has been active in promoting the diaphragm and spermicide use. Counseling includes the new vaginal contraceptive film that contains a N-9 spermicide that dissolves on contact. Demand for the film is just now appearing. Research is needed to determine what degree of protection is provided against HIV infections. The female condom is still expensive and men may also find this method objectionable. Pharmacies are the chief source of barrier methods, but pharmacies do not provide counseling. Efforts have been made to teach sex workers with contraceptive messages. Free condoms have been offered in hourly rate hotels since 1987. A study of condom use within these hotels found that most people do not use the condoms (12%) usage. The range of usage varied with the quality of the hotel; condom use was greatest at more expensive ones (28% versus 5% at cheap hotels). A survey of use of instructional materials left in hotels found that 25% of the customers took the printed materials. PMID:12345033

  20. Limiting Skepticism

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Symons, John

    2011-01-01

    Skeptics argue that the acquisition of knowledge is impossible given the standing possibility of error. We present the limiting convergence strategy for responding to skepticism and discuss the relationship between conceivable error and an agent’s knowledge in the limit. We argue that the skeptic...... must demonstrate that agents are operating with a bad method or are in an epistemically cursed world. Such demonstration involves a significant step beyond conceivability and commits the skeptic to potentially convergent inquiry...

  1. Reduction and enhancement of Plasmodium falciparum transmission by endemic human sera.

    NARCIS (Netherlands)

    Kolk, M. van der; Vlas, S.J. de; Sauerwein, R.W.

    2006-01-01

    Transmission of Plasmodium falciparum from man to mosquito can be affected by human sera. Whereas serum-dependent reduction of transmission has been shown to be reproducible, there is limited evidence for enhancement of transmission. We aimed to assess the prevalence and reproducibility of transmiss

  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. Tractor Transmissions. A Teaching Reference.

    Science.gov (United States)

    American Association for Agricultural Engineering and Vocational Agriculture, Athens, GA.

    The manual was developed as a reference for teaching students about transmissions in farm tractors. The manual is divided into five sections: (1) transmission history, (2) gears and bearings in transmission, (3) sliding-gear transmissions, (4) planetary gearing, and (5) glossary. The working principles of the sliding-gear transmission, the most…

  4. Ultrahigh-Speed Optical Transmission Technology

    CERN Document Server

    Weber, Hans-Georg

    2007-01-01

    Ultrahigh-speed optical transmission technology is a key technology for increasing the communication capacity. In optical fibre networks, the number of wavelength channels and the bit rate per wavelength channel, i.e. the TDM (Time Division Multiplexing) bit rate, determine the transmission capacity. Currently, TDM bit rates of more than 40 Gbit/s require optical signal processing (Optical Time Division Multiplexing, OTDM). OTDM bit rates of up to 1.2 Tbit/s have already been reported. The devices developed for ultrahigh-speed optical transmission are not limited to communication applications only. They are key devices for high-speed optical signal processing, i.e. monitoring, measurement and control, and will thus give a wide technological basis for innovative science and technology. All these aspects of ultrahigh-speed optical transmission technology are described in detail in this book.

  5. 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.

  6. 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)

  7. PHARMACOVIGILANCE: BARRIERS AND CHALLENGES

    Directory of Open Access Journals (Sweden)

    VARMA S. K

    2013-01-01

    Full Text Available Pharmacovigilance is a new discipline which deals with adverse drug or any drug related problems. Pharmacovigilance programme was not bed of roses but its path is laid with challenges and barriers. It is facing obstacles from deficiency from professional health personal to web-based sale of drugs, counterfeit drug to self-medication, etc. It is an integral part of the health sector and identification and reporting of adverse drug effects will have a positive impact on the public health. Improvement in knowledge in pharmacovigilance and communication from the top level to the grass-root level in the health sector will help in proper implementation of the programme. Patient should be educated to report any adverse effects after taking drug and stop relaying on acquiring information related to drugs in web. Proper detection, reporting and analysis would help to implement the programme for the betterment of society.

  8. Countermeasures and barriers

    International Nuclear Information System (INIS)

    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)

  9. Racial Trade Barriers?

    DEFF Research Database (Denmark)

    Bjerre, Jacob Halvas

    Aryanization is associated with Nazi Germany's policies to exclude Jews in the Germany from the economy in the pre-war years, but I will show it was a global policy from 1937. The utopian goal of international Aryanization was the total removal of Jews who traded with Germany anywhere in the world....... This paper analyzes the racial policies pursued in the foreign trade and argues that we need to recognize Aryanization as a world-wide policy in order to fully understand its character and possible consequences. I focus on the pre-war period and analyze the case of Denmark from three different perspectives......: perpetrators, victims and bystanders. The analysis will show that race, economy and foreign trade were combined in an attempt to raise racial trade barriers. This forced the question of German racial policies on the Danish government, Danish-Jewish businesses, and German companies involved in foreign trade...

  10. 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

  11. Identification of Critical Transmission Limits in Injection Impedance Plane

    DEFF Research Database (Denmark)

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

    2012-01-01

    for the critical and characteristic lines in the impedance plane form the basis for a new phasormeasurement based situational awareness method, which uses the results in this paper to identify critical operational boundariesin real time and to visualize the system operating conditions in an informative way...

  12. 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.

  13. Down hole transmission system

    Science.gov (United States)

    Hall, David R.; Hall, Jr., H. Tracy

    2007-07-24

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. The electrically conducting coil comprises at least two generally fractional loops. In the preferred embodiment, the transmission elements are connected by an electrical conductor. Preferably, the electrical conductor is a coaxial cable. Preferably, the MCEI trough comprises ferrite. In the preferred embodiment, the fractional loops are connected by a connecting cable. In one aspect of the present invention, the connecting cable is a pair of twisted wires. In one embodiment the connecting cable is a shielded pair of twisted wires. In another aspect of the present invention, the connecting cable is a coaxial cable. The connecting cable may be disposed outside of the MCEI circular trough.

  14. Transmission of Flu (Influenza)

    Science.gov (United States)

    ... Skip Content Marketing Share this: Main Content Area Flu (Influenza) Transmission How Flu Spreads Coughing and Sneezing People with flu can ... not be shared without washing thoroughly first. The Flu Is Contagious You may be able to pass ...

  15. 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...

  16. 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.

  17. Understanding Ebola Virus Transmission

    OpenAIRE

    Seth Judson; Joseph Prescott; Vincent Munster

    2015-01-01

    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 fil...

  18. Glutamate Transmission in Addiction

    OpenAIRE

    Kalivas, Peter W.; LaLumiere, Ryan; Knackstedt, Lori; Shen, Haowei

    2008-01-01

    Cortico-striatal glutamate transmission has been implicated in both the initiation and expression of addiction related behaviors, such as locomotor sensitization and drug seeking. While glutamate transmission onto dopamine cells in the ventral tegmental area undergoes transient plasticity important for establishing addiction-related behaviors, glutamatergic plasticity in the nucleus accumbens is critical for the expression of these behaviors. This information points to the value of exploring ...

  19. Continuously Variable Transmission

    Science.gov (United States)

    Grana, D. C.

    1985-01-01

    Chain slides along two cones, in novel transmission concept. Transmission includes chain drive between two splined shafts. Chain sprockets follow surfaces of two cones. As one chain sprocket moves toward smaller diameter other chain sprocket moves toward larger diameter, thereby changing "gear" ratio. Movement initiated by tension applied to chain by planetary gear mechanism. Device positive, simple, and efficient over wide range of speed ratios.

  20. Gravity wave transmission diagram

    Science.gov (United States)

    Tomikawa, Yoshihiro

    2016-07-01

    A possibility of gravity wave propagation from a source region to the airglow layer around the mesopause has been discussed based on the gravity wave blocking diagram taking into account the critical level filtering alone. This paper proposes a new gravity wave transmission diagram in which both the critical level filtering and turning level reflection of gravity waves are considered. It shows a significantly different distribution of gravity wave transmissivity from the blocking diagram.

  1. Analog data transmission via fiber optics

    International Nuclear Information System (INIS)

    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

  2. UHV交流输电线路有源干扰下无方向信标台功率限值的分析%Analysis of Non-directional Radio Beacon Power Limit Under the Condition of Active Interference Caused by UHV AC Transmission Line

    Institute of Scientific and Technical Information of China (English)

    周铖路; 翁木云; 陈凤

    2015-01-01

    有关UHV交流输电线路与无方向信标台电磁兼容方面的研究主要集中在防护距离的分析,对间距无法满足要求时的兼容问题研究较少。为此,从台站频谱参数入手,分析特高压交流输电线路有源干扰下无方向信标台的发射功率限值。首先介绍无方向信标台的工作原理及配置区域,然后分析UHV交流输电线路对台站的干扰机理,最后根据飞行航迹,以防护率为干扰判别依据,结合防护距离的研究,分别针对航路无方向信标台、近距无方向信标台和远距无方向信标台进行有效辐射功率的分析。结果表明,在给定条件下,对于航路和远距无方向信标台,有效辐射功率分别大于5.298 W、5.273 W时,机载无线电罗盘不受干扰;对于近距无方向信标台,与输电线路始终满足兼容的要求,无需分析限值。%The EMC research between UHV AC transmission line and non-directional radio beacon mainly focused on the protection distance while the study of EMC is little when the protection distance cannot meet the requirements. Therefore, the non-directional radio beacon power limit under the condition of active interference caused by UHV AC transmission line is analyzed from the aspect of spectrum parameters. Firstly, the working principle and configuration area of non-directional radio beacon are introduced. Then the interference mechanism of non-directional radio beacon from UHV AC transmission line is analyzed. Finally, the effective radiated power (ERP) of route non-directional radio beacon, close non-directional radio beacon and distance non-directional radio beacon are analyzed according to the flight path and protection ratio in combination with protection distance research. The results show that under the given conditions, route non-directional radio beacon and distance non-directional radio beacon’s ERP should be greater than 5.298 W and 5.273 W respectively to keep

  3. 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).

  4. Deposition of SiOx barrier films by O2/TMDSO RF-PECVD

    Institute of Scientific and Technical Information of China (English)

    Zhou Mei-Li; Fu Ya-Bo; Chen Qiang; Ge Yuan-Jing

    2007-01-01

    This paper reports that the SiOx barrier films are deposited on polyethylene terephthalate substrate by plasmaenhanced chemical vapour deposition (PECVD) for the application of transparent barrier packaging. The variations of O2/Tetramethyldisiloxane (TMDSO) ratio and input power in radio frequency (RF) plasma are carried out to optimize barrier properties of the SiOx coated film. The properties of the coatings are characterized by Fourier transform infrared,water wpour transmission rate (WVTR), oxygen transmission rate (OTR), and atomic force microscopy analysers. It is found that the O2/TMDSO ratio exceeding 2:1 and the input power over 200 W yield SiOx films with low carbon contents which can be good to the barrier (WVTR and OTR) properties of the SiOx coatings. Also, the film properties not only depend on oxygen concentration of the inlet gas mixtures and input power, but also relate to the surface morphology of the coating.

  5. Electron Holography of Barrier Structures in Co/ZrAlOx/Co Magnetic Tunnel Junctions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; ZHU Tao; SHEN Feng; SHENG Wen-Ting; WANG Wei-Gang; XIAO John Q; ZHANG Ze

    2005-01-01

    @@ We investigate the potential profiles and elemental distribution of barriers in Co/ZrAlOx/Co magnetic tunnel junctions (MTJs) using electron holography (EH) and scanning transmission electron microscopy. The MTJ barriers are introduced by oxidizing a bilayer consisting with a uniform 0.45-nm Al layer and a wedge-shaped Zr layer (0-2 nm). From the scanning transmission electron microscopy, AlOx and ZrOx layers are mixed together,indicating that compact AlOx layer cannot be formed in such a bilayer structure of barriers. The EH results reveal that there are no sharp interfaces between the barrier and magnetic electrodes, which may be responsible for a smaller tunnelling magnetoresistance compared with the MTJs of Co/AlOx/Co.

  6. Optical limiting by chemically enhanced bacteriorhodopsin films

    Science.gov (United States)

    Song, Q. Wang; Zhang, Chungping; Gross, Richard; Birge, Robert

    1993-05-01

    Measurements of effective nonlinearity of a chemically enhanced bacteriorhodopsin film are presented, using 2-scan method. Optical limiting properties and the film's nonlinear transmission properties of the film are also studied.

  7. 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…

  8. Wireless data signal transmission system

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver.......The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver....

  9. Composite Based EHV AC Overhead Transmission Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard

    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...

  10. Priority image transmission in wireless sensor networks

    International Nuclear Information System (INIS)

    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.

  11. 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

  12. Adjusted barrier management to improve glass eel migration at an estuarine barrier

    OpenAIRE

    A. Mouton; Buysse, D.; STEVENS, M.; Van den Neucker, T.; Coeck, J.

    2013-01-01

    European eel Anguilla Anguilla (L.) populations have declined dramatically during the last decades and are now among the most critically endangered fish populations in Europe. The limitation of upstream migration of glass eels is considered to be one of the key factors reducing eel populations. The migration of eels in their juvenile stage (glass eels) was studied, and options to improve eel passage at a tidal barrier complex at the mouth of the Yser River, Flanders, Belgium, were assessed. G...

  13. 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

  14. 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.

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

    International Nuclear Information System (INIS)

    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

  16. Static and dynamic fusion barriers in heavy-ion reactions

    International Nuclear Information System (INIS)

    We have calculated the potential energy of two interacting nuclei within the liquid-drop model including the nuclear proximity energy. We use a two-parameter family of shapes which simply describes the path leading from two separated nuclei to the spherical compound nucleus. Double-humped fusion barriers appear when Z1Z2> or approx.1800+-100. The inner barrier is the highest for Z1Z2> or approx.2300+-100. The existence and the shape of the external minimum may be at origin of the development of fusion-fission or fast-fission phenomena. Our phenomenological dynamic model depends only on one parameter: the radial friction coefficient, fixed once and for all. The empirical barrier heights are very well reproduced. For very heavy systems (Z1Z2> or approx.2100+-100, alternatively (Z2/A)sub(eff)> or approx.38 or xsub(eff)> or approx.0.8), a dynamic fusion barrier appears, significantly higher than the static one and in close agreement with the experimental data. This dynamic barrier is mostly governed by the entrance channel, no evidence for dynamic deformations being found. The slope of the fusion cross sections is better reproduced if the angular momentum dissipation rule varies from the sticking limit for medium systems to the sliding limit for very heavy systems. The possibility of forming superheavy elements is strongly hindered by this double-humped dynamic barrier. (orig.)

  17. Provider barriers to telemental health: obstacles overcome, obstacles remaining.

    Science.gov (United States)

    Brooks, Elizabeth; Turvey, Carolyn; Augusterfer, Eugene F

    2013-06-01

    Many providers are hesitant to use telemental health technologies. When providers are queried, various barriers are presented, such as the clinician's skepticism about the effectiveness of telemental health (TMH), viewing telehealth technologies as inconvenient, or reporting difficulties with medical reimbursement. Provider support for TMH is critical to its diffusion because clinicians often serve as the initial gatekeepers to telehealth implementation and program success. In this article, we address provider concerns in three broad domains: (1) personal barriers, (2) clinical workflow and technology barriers, and (3) licensure, credentialing, and reimbursement barriers. We found evidence that, although many barriers have been discussed in the literature for years, advancements in TMH have rapidly reduced obstacles for its use. Improvements include extensive opportunities for training, a growing evidence base supporting positive TMH outcomes, and transformations in technologies that improve provider convenience and transmission quality. Recommendations for further change are discussed within each domain. In particular, it is important to grow and disseminate data underscoring the promise and effectiveness of TMH, integrate videoconferencing capabilities into electronic medical record platforms, expand TMH reimbursement, and modify licensure standards.

  18. Probability of HIV Transmission During Acute Infection in Rakai, Uganda

    OpenAIRE

    Pinkerton, Steven D.

    2007-01-01

    Accurate estimates of the probability of HIV transmission during various stages of infection are needed to inform epidemiological models. Very limited information is available about the probability of transmission during acute HIV infection. We conducted a secondary analysis of published data from the Rakai, Uganda seroconversion study. Mathematical and computer-based models were used to quantify the per-act and per-partnership transmission probabilities during acute and chronic HIV infection...

  19. Magnetically tunable broadband transmission through a single small aperture

    OpenAIRE

    Ke Bi; Wenjun Liu; Yunsheng Guo; Guoyan Dong; Ming Lei

    2015-01-01

    Extraordinary transmission through a small aperture is of great interest. However, it faces a limitation that most of approaches can not realize the tunable transmission property, which is not benefit for the miniaturization of the microwave system. Here, we demonstrate a magnetically tunable broadband transmission through a small aperture. By placing two ferrite rods symmetrically on both sides of a single small aperture, the strongly localized electromagnetic fields are effectively coupled ...

  20. 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.

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

    International Nuclear Information System (INIS)

    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

  2. Mobilitet, Barrierer & Muligheder

    DEFF Research Database (Denmark)

    Petersen, Mimi Judidoleslami

    2011-01-01

    som en vej ud af irakiske Kurdistan, men ikke tilbage til Danmark. Drengene fra familier med bedre økonomiske ressourcer giver udtryk for, ønske om at rejse til andre lande. På grund af begrænsede sproglige kompetencer oplever hovedparten af de unge (både i Danmark og i irakiske Kurdistan) barrierer i...... forhold til at indgå i et kurdisk fællesskab. I forhold til de repatrierede unge er det netop manglende sproglig kompetence, der har skabt mange problemer for dem i bl.a. skolesammenhænge. Familier med bedre økonomiske ressourcer har forsøgt at råde bod på dette gennem ansættelse af privat sproglærere...... af hjem og belonging som viser sig i form af en transnational orientering. Og i denne transnationale orientering får Danmark en central placering. Det samme kan man med en vis forsigtighed sige om køn dvs. at pigerne retter sig mere mod Danmark. Men det at Danmark i pigernes transnationale...

  3. 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)

  4. Development of engineered barrier

    International Nuclear Information System (INIS)

    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 and 316L 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)

  5. Wave Scattering by Double Slotted Barriers in A Steady Current: Experiments

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The adoption of slotted breakwaters can be an ideal option in the protection of very large near-shore floating structures that may extend offshore to a considerable water depth. In this paper, we experimently investigated the behaviour of wave transmission and reflection coefficients of double slotted barriers in the presence of a steady opposing current. The experimental results show that opposing currents have only minor effects on wave reflection, but can significantly reduce the wave transmission through double slotted barriers. The experimental results suggest that coastal currents should be taken into consideration for an economical design of slotted breakwaters.

  6. 2006 Final Transmission Proposal.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    2005-06-01

    This Record of Decision (ROD) contains the decisions of the Administrator of the Bonneville Power Administration BPABPA with respect to the adoption of transmission and ancillary services rates for the two-year rate period beginning October 1, 2005, and ending September 30, 2007 (fiscal years (FY) 2006-2007)(2006 Final Transmission and Ancillary Services Rate Proposal). These decisions are based on the record compiled in this rate proceeding. The transmission and ancillary services rates adopted in this ROD are the rates proposed as a result of a comprehensive settlement agreement between BPA's Transmission Business Line (BPA-TBL) and a diverse group of transmission customers, including BPA's Power Business Line (BPA-PBL), regional investor-owned utilities, partial and full requirements customers of the BPA-PBL, Direct Services Industrial (DSI) customers, and merchant generators. The decisions in this ROD to adopt the rates and charges proposed by the settlement agreement are not intended to create or imply any factual , legal, procedural or substantive precedent, or to create agreement to any underlying principle or methodology.

  7. Ultrahigh Transmission Optical Nanofibers

    CERN Document Server

    Hoffman, J E; Grover, J A; Solano, P; Kordell, P R; Wong-Campos, J D; Orozco, L A; Rolston, S L

    2014-01-01

    We present a procedure for reproducibly fabricating ultrahigh transmission optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode transmissions of 99.95 $ \\pm$ 0.02%, which represents a loss from tapering of 2.6 $\\,\\times \\,$ 10$^{-5}$ dB/mm when normalized to the entire stretch. When controllably launching the next family of higher-order modes on a fiber with 195 mm stretch, we achieve a transmission of 97.8 $\\pm$ 2.8%, which has a loss from tapering of 5.0 $\\,\\times \\,$ 10$^{-4}$ dB/mm when normalized to the entire stretch. Our pulling and transfer procedures allow us to fabricate optical nanofibers that transmit more than 400 mW in high vacuum conditions. These results, published as parameters in our previous work, present an improvement of two orders of magnitude less loss for the fundamental mode and an increase in transmission of more than 300% for higher-order modes, when following the protocols detailed in this paper. We extract from the transmission during the pull, the only reported...

  8. Healthcare barriers of refugees post-resettlement.

    Science.gov (United States)

    Morris, Meghan D; Popper, Steve T; Rodwell, Timothy C; Brodine, Stephanie K; Brouwer, Kimberly C

    2009-12-01

    The majority of refugees spend the greater part of their lives in refugee camps before repatriation or resettlement to a host country. Limited resources and stress during residence in refugee camps can lead to a variety of acute and chronic diseases which often persist upon resettlement. However, for most resettled refugees little is known about their health needs beyond a health assessment completed upon entry. We conducted a qualitative pilot-study in San Diego County, the third largest area in California, USA for resettling refugees, to explore health care access issues of refugees after governmental assistance has ended. A total of 40 guided in-depth interviews were conducted with a targeted sample of informants (health care practitioners, employees of refugee serving organizations, and recent refugee arrivals) familiar with the health needs of refugees. Interviews revealed that the majority of refugees do not regularly access health services. Beyond individual issues, emerging themes indicated that language and communication affect all stages of health care access--from making an appointment to filling out a prescription. Acculturation presented increased stress, isolation, and new responsibilities. Additionally, cultural beliefs about health care directly affected refugees' expectation of care. These barriers contribute to delayed care and may directly influence refugee short- and long-term health. Our findings suggest the need for additional research into contextual factors surrounding health care access barriers, and the best avenues to reduce such barriers and facilitate access to existing services.

  9. Transmission Bandwidth Expansion of SI-POF Using WDM-Pulse-Position Modulations

    Institute of Scientific and Technical Information of China (English)

    Katsumi; Takano; Eiji; Matsumoto; Kiyoshi; Nakagawa

    2003-01-01

    WDM-Pulse-position modulation technique in SI-POF transmission is proposed to overcome the limitation from mode dispersion. It can expand the flat transmission bandwidth to 80MHz with 100m-fiber length.

  10. Variable parallax barrier spacing in autostereoscopic displays

    Science.gov (United States)

    Yoon, Seon Kyu; Khym, Sungwon; Kim, Hyun-Woo; Kim, Sung-Kyu

    2016-07-01

    In general, multi-view autostereoscopic displays can only provide autostereoscopic images with little crosstalk at the optimum viewing distance (OVD) in the depth direction, limiting the mobility of viewers. Therefore, this paper proposes a method of increasing viewer mobility in the depth direction by varying the distance separating the parallax barrier and the display. Computer simulations and experiments were conducted to verify changes in the OVD resulting from the application of the proposed method. The results showed that the proposed method is effective at changing the OVD with respect to changes in the viewing distance. Therefore this method minimizes changes in the 3D image quality due to the viewer's depth location.

  11. 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"--

  12. Dynamic lung transmission studies

    International Nuclear Information System (INIS)

    The aim of this study was to develop a non-invasive method for determining regional lungvolumes, which could replace bronchospirometry in routine clinical use. Transmission through the thorax of sup(99m)Tc-gammarays is measured by means of a gamma camera on line with a computer. The technique of measurement and data analysis is described and tested in several series of phantom studies. The results proved to be good: the mean difference with the real volumes was -4%. The error varied between -10% and +1. Transmission studies and bronchospirometry are compared in a group of 11 patients and there proved to be a good correspondence between the results of these methods. It is concluded that transmission experiments can determine the vital capacity of both lungs as a whole as accurately as spirometry and allows the measurement of vital capacity for each lung separately with the same accuracy as bronchospirometry. (Auth.)

  13. Aerosol Transmission of Filoviruses.

    Science.gov (United States)

    Mekibib, Berhanu; Ariën, Kevin K

    2016-01-01

    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. PMID:27223296

  14. 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.

  15. 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

  16. 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.

  17. Permeation barrier properties of thin oxide films on flexible polymer substrates

    International Nuclear Information System (INIS)

    Solar cells and organic electronic devices require an encapsulation to ensure sufficient lifetime. Key parameters of the encapsulation are permeation barrier, UV stability, temperature stability, optical transmission spectra and mechanical stability. The requirements depend very much on the specific application. Many work groups suggest multilayer stacks to meet the permeation requirements. In this paper the permeation barrier properties of the different constituents of such a multilayer stack are characterized. Different layer materials are compared regarding their water vapour and oxygen permeability as well as the influence of process parameters is examined. Finally temperature dependent permeation measurements are used to characterize the permeation mechanisms in the different constituents of the multilayer barrier

  18. Transmission positron microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Doyama, Masao [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan)]. E-mail: doyama@ntu.ac.jp; Kogure, Yoshiaki [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan); Inoue, Miyoshi [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan); Kurihara, Toshikazu [Institute of Materials Structure Science (IMSS), High Energy Accelerator, Research Organization (KEK), Ohno 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Yoshiie, Toshimasa [Reactor Research Institute, Kyoto University, Noda, Kumatori, Osaka 590-0451 (Japan); Oshima, Ryuichiro [Research Institute for Advanced Science and Technology, Osaka Prefecture University (Japan); Matsuya, Miyuki [Electron Optics Laboratory (JEOL) Ltd., Musashino 3-1-2, Akishima 196-0021 (Japan)

    2006-02-28

    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.

  19. Nosocomial Transmission of SARS.

    Science.gov (United States)

    Lee, Nelson; Sung, Joseph J.Y.

    2003-12-01

    Severe acute respiratory syndrome is a newly emerged infectious disease with moderately high transmissibility. Nosocomial outbreaks were responsible for the propagation of the epidemic worldwide. Health care workers (HCW) are at particular high risk because of their close contact with patients, involvement in medical procedures, and handling of excreta/fomites. Good hospital organization and appropriate infection control strategies are essential to prevent/interrupt disease transmission from patients to HCWs (and vice versa) and among inpatients and HCWs themselves. Education and training should target broadly to all HCWs.

  20. 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

  1. Informatization barriers of logistics process management in production company

    OpenAIRE

    Joanna WALASEK

    2015-01-01

    This article is an attempt to characterize informatization barriers of logistics processes management in a production company which provides automotive parts. Threats of successful implementation of Enterprise Resource Planning Systems include: community barriers; organizational barriers; communication barriers; formal barriers; legal barriers; not prepared implementation team barrier; substantive barrier. Proper identification of barriers and solving them are the right way to implement Enter...

  2. Stretchable gas barrier achieved with partially hydrogen-bonded multilayer nanocoating.

    Science.gov (United States)

    Holder, Kevin M; Spears, Benjamin R; Huff, Molly E; Priolo, Morgan A; Harth, Eva; Grunlan, Jaime C

    2014-05-01

    Super gas barrier nanocoatings are recently demonstrated by combining polyelectrolytes and clay nanoplatelets with layer-by-layer deposition. These nanobrick wall thin films match or exceed the gas barrier of SiOx and metallized films, but they are relatively stiff and lose barrier with significant stretching (≥ 10% strain). In an effort to impart stretchability, hydrogen-bonding polyglycidol (PGD) layers are added to an electrostatically bonded thin film assembly of polyethylenimine (PEI) and montmorillonite (MMT) clay. The oxygen transmission rate of a 125-nm thick PEI-MMT film increases more than 40x after being stretched 10%, while PGD-PEI-MMT trilayers of the same thickness maintain its gas barrier. This stretchable trilayer system has an OTR three times lower than the PEI-MMT bilayer system after stretching. This report marks the first stretchable high gas barrier thin film, which is potentially useful for applications that require pressurized elastomers. PMID:24700525

  3. Spin-dependent tunnelling through an indirect double-barrier structure

    Institute of Scientific and Technical Information of China (English)

    Wang Rui; Zhang Cun-Xi; Wang Jian-Ming; Liang Jiu-Qing

    2008-01-01

    We use the transfer matrix method to study the quantum tunnelling through an indirect-band-gap double-barrier like the GaAs/A1As/GaAs/A1As/GaAs heterostructures along the[001]axis,which is described by the tight-binding model.The X-valley quasi-bound state gives rise to the Fano resonance different from the direct double-barrier transition in a resonance-tunnelling diode.The quantitative calculations demonstrate that a relatively high spin-polarization of the transmission probability can be achieved as compared with the single-barrier tunnelling case.Moreover the extension to the multi-barrier device is provided and leads to an important observation that the spin polarization increases with the number of barriers.

  4. Ultrathin Mo/MoN bilayer nanostructure for diffusion barrier application of advanced Cu metallization

    International Nuclear Information System (INIS)

    Ultrathin Mo (5 nm)/MoN (5 nm) bilayer nanostructure has been studied as a diffusion barrier for Cu metallization. The Mo/MoN bilayer was prepared by magnetron sputtering and the thermal stability of this barrier is investigated after annealing the Cu/barrier/Si film stack at different temperatures in vacuum for 10 min. The failure of barrier structure is indicated by the abrupt increase in sheet resistance and the formation of Cu3Si phase proved by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). High resolution transmission electron microscopy (HRTEM) examination suggested that the ultrathin Mo/MoN barrier is stable and can prevent the diffusion of Cu at least up to 600 deg. C.

  5. 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.

  6. Smart Transmission Grids - Benefits and Risks

    Directory of Open Access Journals (Sweden)

    Velasco-Ramírez E.

    2013-01-01

    Full Text Available Nowadays the Power Systems are working near their stability limits, for this reason it is necessary and essential a transition to new transmission systems that ensure efficient delivery of electrical energy, with the objective to prevent “blackouts” that causesignificant losses in the economy of any country in the world. This paper analyzes important elements to consider having a healthy and efficient transition from a power grid vertically integrated into a smart transmission grid. A comparative analysis in the model, development, benefits and risks of the implementation of these systems, between two of the main marc of references of smart grids, the EU and the USA is presented.

  7. Modelling of acoustic transmission through perforated layer

    Directory of Open Access Journals (Sweden)

    Lukeš V.

    2007-10-01

    Full Text Available The paper deals with modeling the acoustic transmission through a perforated interface plane separating two halfspaces occupied by the acoustic medium. We considered the two-scale homogenization limit of the standard acoustic problem imposed in the layer with the perforated periodic structure embedded inside. The homogenized transmission conditions govern the interface discontinuity of the acoustic pressure associated with the two halfspaces and the magnitude of the fictitious transversal acoustic velocity. By numerical examples we illustrate this novel approach of modeling the acoustic impedance of perforated interfaces.

  8. A brief sexual barrier intervention for women living with AIDS: Acceptability, use, and ethnicity

    OpenAIRE

    Jones, Deborah L; Weiss, Stephen M; Malow, Robert; ISHII, MARY; Devieux, Jessy; Stanley, Heidi; Cassells, Andrea; Tobin, Jonathan N.; Brondolo, Elizabeth; LaPerriere, Arthur; Efantis-Potter, Jonell; O'Sullivan, Mary Jo; Schneiderman, Neil

    2001-01-01

    Interventions aimed at reducing sexual transmission of human immunodeficiency virus/sexually transmitted diseases (HIV/STDs) have focused primarily on male condom use among seronegative men and women. However, female-controlled sexual barriers (female condoms and vaginal microbicides) offer women living with acquired immunodeficiency syndrome (AIDS) alternative methods to protect themselves and others from disease transmission. A pilot behavioral intervention was conducted to increase sexual ...

  9. Colossal optical transmission through buried metal gratings (Presentation Recording)

    Science.gov (United States)

    Roberts, Christopher M.; Liu, Runyu; Zhao, Xiang; Yu, Lan; Li, Xiuling; Wasserman, Daniel M.; Podolskiy, Viktor A.

    2015-09-01

    In Extraordinary Optical Transmission (EOT), a metallic film perforated with an array of [periodic] apertures exhibits transmission over 100% normalized to the total aperture area, at selected frequencies. EOT devices have potential applications as optical filters and as couplers in hybrid electro-optic contacts/devices. Traditional passive extraordinary optical transmission structures, typically demonstrate un-normalized transmission well below 50%, and are typically outperformed by simpler thin-film techniques. To overcome these limitations, we demonstrate a new breed of extraordinary optical transmission devices, by "burying" an extraordinary optical transmission grating in a dielectric matrix via a metal-assisted-chemical etching process. The resulting structure is an extraordinary optical transmission grating on top of a dielectric substrate with dielectric nano-pillars extruded through the grating apertures. These structures not only show significantly enhanced peak transmission when normalized to the open area of the metal film, but more importantly, peak transmission greater than that observed from the bare semiconductor surface. The structures were modeled using three-dimensional rigorous coupled wave analysis and characterized experimentally by Fourier transform infrared reflection and transmission spectroscopy, and the good agreement between the two has been demonstrated. The drastic enhancement of light transmission in our structures originates from structuring of high-index dielectric substrate, with pillars effectively guiding light through metal apertures.

  10. Climatic suitability for malaria transmission in Africa, 1911–1995

    OpenAIRE

    Small, Jennifer; Goetz, Scott J; Simon I. Hay

    2003-01-01

    Time series analysis of a climate-driven model of malaria transmission shows limited evidence for an increase in suitability during the last century across Africa. Outside areas where climate was always or never suitable,

  11. 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...

  12. Dilemmas of Cultural Transmission

    Science.gov (United States)

    Kováts-Németh, Mária

    2016-01-01

    The fundamental problem of the 21st century is that in the modern civilization "the transmission of values is not stable." There is nothing, except for the natural sense of justice and some legal traditions, which would exercise selective power on social behavior. At a critical time in 1949 Albert Szent-Györgyi drew the attention to the…

  13. Autonomous data transmission apparatus

    Science.gov (United States)

    Kotlyar, Oleg M.

    1997-01-01

    A autonomous borehole data transmission apparatus for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters.

  14. Improving Transmission Planning

    OpenAIRE

    Saraswat, Kavita; Gupta, Amol

    2016-01-01

    Development of power transmission networks requires long lead times and substantial capital. Optimization of investment is especially critical in fast-growing economies such as India’s, where there are competing demands on financial resources, and utilities need to maintain adequate cash flow to expand electricity service for economic growth and poverty reduction. As shown by examples from...

  15. Barriers in diabetes self management

    OpenAIRE

    Rising, Carl Johan; Lauwersen, Asbjørn Flyger; Stoustrup, Sune Wiingaard

    2013-01-01

    This project seeks to expand on the question: What barriers may occur in diabetes patients' self-care, and how can doctors and patients communicate across professionalism? This project deals with the barrier that may arise between the transfer of highly professional knowledge and patient. The project seeks to create an understanding on how diabetes patients, which is the target audience, understands and experience their illness, and thereby mapping key elements for further focus, to better th...

  16. Transmission mechanisms of an emerging insect-borne rickettsial pathogen

    OpenAIRE

    Brown, Lisa D.; Kaikhushroo H Banajee; Lane D Foil; Macaluso, Kevin R.

    2016-01-01

    Background Vector-borne pathogens must overcome arthropod infection and escape barriers (e.g. midgut and salivary glands) during the extrinsic incubation period (EIP) before subsequent transmission to another host. This particular timespan is undetermined for the etiological agent of flea-borne spotted fever (Rickettsia felis). Artificial acquisition of R. felis by blood-feeding cat fleas revealed dissemination to the salivary glands after seven days; however, this length of time is inconsist...

  17. [Transmissible spongiform encephalopathies: neuroinfections with unconventional immune reactions].

    Science.gov (United States)

    Mitrová, E

    1997-04-01

    Transmissible spongiform encephalopathies (TSE) as well as the properties of the major component of the infectious agent-prion, and the most important human and animal prion diseases are characterized. Considering the recent biochemical and molecular biological data, possible explanations of natural resistance, species barrier and lack of the immune response to the unconventional infectious particles are presented. Finally the importance of immunoblotting and immunostaining as the most specific confirmation of TSE diagnosis is underlined. (Ref. 11.)

  18. Quantum pumping in graphene nanoribbons at resonant transmission

    OpenAIRE

    Grichuk, E.; Manykin, E.

    2010-01-01

    Adiabatic quantum charge pumping in graphene nanoribbon double barrier structures with armchair and zigzag edges in the resonant transmission regime is analyzed. Using recursive Green's function method we numerically calculate the pumped charge for pumping contours encircling a resonance. We find that for armchair ribbons the whole resonance line contributes to the pumping of a single electron (ignoring double spin degeneracy) per cycle through the device. The case of zigzag ribbons is more i...

  19. Global interrupt and barrier networks

    Science.gov (United States)

    Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E; Heidelberger, Philip; Kopcsay, Gerard V.; Steinmacher-Burow, Burkhard D.; Takken, Todd E.

    2008-10-28

    A system and method for generating global asynchronous signals in a computing structure. Particularly, a global interrupt and barrier network is implemented that implements logic for generating global interrupt and barrier signals for controlling global asynchronous operations performed by processing elements at selected processing nodes of a computing structure in accordance with a processing algorithm; and includes the physical interconnecting of the processing nodes for communicating the global interrupt and barrier signals to the elements via low-latency paths. The global asynchronous signals respectively initiate interrupt and barrier operations at the processing nodes at times selected for optimizing performance of the processing algorithms. In one embodiment, the global interrupt and barrier network is implemented in a scalable, massively parallel supercomputing device structure comprising a plurality of processing nodes interconnected by multiple independent networks, with each node including one or more processing elements for performing computation or communication activity as required when performing parallel algorithm operations. One multiple independent network includes a global tree network for enabling high-speed global tree communications among global tree network nodes or sub-trees thereof. The global interrupt and barrier network may operate in parallel with the global tree network for providing global asynchronous sideband signals.

  20. Economic alternatives for containment barriers

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J. [Geo-Con, Inc., Monroeville, PA (United States)

    1997-12-31

    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.

  1. 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.

  2. Do Children's Behavior Problems Limit Poor Women's Labor Market Success?

    Science.gov (United States)

    Coley, Rebekah Levine; Ribar, David; Votruba-Drzal, Elizabeth

    2011-01-01

    Economically disadvantaged mothers face numerous barriers to stable, quality employment opportunities. One barrier that has received limited attention in previous research is having a child with significant psychological or behavioral problems. Using a representative sample of low-income mothers and early adolescent children from the Three-City…

  3. Physical Activity and Youth with Disabilities: Barriers and Supports

    Science.gov (United States)

    Block, Martin E.; Taliaferro, Andrea; Moran, Tom

    2013-01-01

    Physical activity and active use of leisure time is important for everyone but particularly important for youth with disabilities. Unfortunately, youth with disabilities often have a difficult time or are even excluded from participating in physical activity due to limited physical and cognitive skills, attitudinal barriers in the community, lack…

  4. Identifying Barriers to the Remix of Translated Open Educational Resources

    Science.gov (United States)

    Amiel, Tel

    2013-01-01

    Remix is touted as one of the most important practices within the field of open educational resources (OER). But remixing is still not mainstream practice in education and the barriers and limitations to remix are not well known. In this article we discuss the design and development of a print and web-based booklet created to introduce the topic…

  5. 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…

  6. 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...

  7. 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.

  8. Performance of engineered barriers for low-level waste

    International Nuclear Information System (INIS)

    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

  9. (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.

  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. 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)

  12. 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 coping with

  13. Data transmission networks

    Science.gov (United States)

    Alexovich, Robert

    1990-01-01

    A task order was written by the High Resolution, High Frame Rate Video Technology (HHVT) project engineers to investigate data compression techniques that could be applied to the HHVT system, and both existing and planned downlink/uplink capabilities of the Space Shuttle and Space Station Freedom. The following tasks were included: (1) Investigate signal channel availability and determine both the maximum possible data rate and the average data rate; (2) Identify time blocks for HHVT video transmission assuming time sharing and interruptions in the communication links; (3) Determine the bit error rates to be expected; and (4) Define the transmit and receive interfaces. A summary chart of the data transmission capabilities for Tracking and Data Relay Satellite System (TDRSS), the Space Shuttle, Space Station Freedom, Spacelab, and USLab are also presented.

  14. 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.

  15. ECRH transmission system

    International Nuclear Information System (INIS)

    The M.I.T. gyrotron group operates a 140 GHz, short pulse (1μs) gyrotron with output power, at present, of up to 175 kW. Output radiation has been obtained in several modes, including TE03 at 140 GHz, TE23 at 137 GHz, TE42 at 128 GHz and TE52 at 145 GHz. Studies have been carried out of the mode purity, both in frequency and in space, of gyrotron output radiation. These studies investigate parasitic mode excitation and mode conversion of gyrotron output power. Far field patterns of gyrotron radiation have been investigated to determine mode symmetry and purity. These results are useful in estimating the efficiency of various transmission systems. Finally, a new approach to quasi-optical transmission lines and mode converters, using axisymmetric optics, is suggested

  16. 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.

  17. Global wireless power transmission

    OpenAIRE

    Glaser, Peter E.

    1995-01-01

    Economic and environmental pressures require the development of technologies that are compatible with the Earth’s environment and acceptable to society. An emerging power supply option based on Nikola Tesla’s concept of wireless power transmission (WPT) can be applied to transmit power over intercontinental distances with power relay satellites (PRS) [1] to access renewable energy sources at undeveloped or underutilized remote sites, and to convert solar energy in space for use on Earth on a ...

  18. Control of schistosomiasis transmission

    OpenAIRE

    Luiz C. de S. Dias; Oswaldo Marçal Jr.; GLASSER Carmem M.

    1995-01-01

    Despite the success of control programmes, schistosomiasis is still a serious public health problem in the world. More than 70 countries where 200 million individuals are evaluated to be infected of a total 600 million at risk. Though there have been important local success in the control of transmission, globally the infection has increased. Economic constrains in developing countries, environmental changes associated with migration and water resources development have been blocking the prog...

  19. Transmission of Helicobacter pylori

    OpenAIRE

    Axon, Anthony T. R.

    1999-01-01

    Helicobacter gastroduodenitis is a serious chronic infectious disease that is responsible for widespread morbidity and mortality. An understanding of the way in which it spreads is fundamentally important when considering measures for its control. Its prevalence is highest in the developing world and in individuals with a disadvantaged socio-economic childhood. The disease is believed to be contracted during the early years of life. A faeco-oral mode of transmission is considered by many to b...

  20. 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.

  1. Super stretchy polymer multilayer thin films with tunable gas barrier

    Science.gov (United States)

    Xiang, Fangming; Ward, Sarah; Givens, Tara; Grunlan, Jaime

    2015-03-01

    Super stretchy multilayer thin film assemblies with tunable gas barrier were fabricated using layer-by-layer (LbL) assembly. Unlike ionically-bonded gas barrier coatings that exhibit mud-cracking after 10% strain, hydrogen-bonded polyethylene oxide (PEO) and polyacrylic acid (PAA) multilayer thin films show no cracking after 100% strain due to low modulus. It is believed that the exceptional elasticity of this thin film originates from the intrinsic elasticity of PEO and the moderate hydrogen bond strength between PEO and PAA. The oxygen transmission rate (OTR) of a 1.58 mm thick natural rubber sheet can be reduced 10 times with a 367-nm-thick PAA/PEO nanocoating. This gas barrier improvement is largely retained after 100% strain. The modulus and oxygen permeability of PAA/PEO assembly can be tailored through altering the assembling pH. By setting the assembling pH to 2.75, a 50% reduction in permeability can be achieved, while maintaining the elasticity of the assembly. These findings mark the first super stretchy gas barrier thin film, which is useful for elastomeric substrates designed to hold air pressure.

  2. NB Power Transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, J. [NB Power Transmission, Fredericton, NB (Canada)

    2006-07-01

    The NB Power Transmission System operates 6700 km of transmission lines having voltages of 69 kV, 138 kV, 230 kV, and 345 kV. The history of lightning protection on this transmission system was presented. Lightning protection with shield wires has been applied selectively on the 69 kV and 138 kV lines and has been applied to all lines in the 230 kV and 345 kV range. Beginning in 2000, line arresters were installed on selected 69 kV and 138 kV lines. It was noted that although overhead shield wires are commonly installed to capture lightning strikes and shield the conductors, problems can occur if the electrical flashover of insulators result in a line to ground fault. Good grounding is needed to ensure that lightning enters the ground from the tower. The new approach is to install line arresters on structures without overhead shield wires. Line arresters are surge arresters applied in parallel with the insulator string. This new line arrester technology was tested by installing nearly 1200 arresters in the Saint John area. This paper described the reasons for choosing line arresters over shield wires and presented the methods of installation. The problems and failure rates of the installed line arresters were presented along with solutions, including solutions to protect lines against lightning in areas with heavy icing. Recommendations for future research into the use, application and development of line arresters were also presented. tabs., figs.

  3. Transparent conductive gas-permeation barriers on plastics by atomic layer deposition.

    Science.gov (United States)

    Chou, Chun-Ting; Yu, Pei-Wei; Tseng, Ming-Hung; Hsu, Che-Chen; Shyue, Jing-Jong; Wang, Ching-Chiun; Tsai, Feng-Yu

    2013-03-25

    A mixed-deposition atomic layer deposition process produces Hf:ZnO films with uniform dopant distribution and high electrical conductivity (resistivity = 4.5 × 10(-4) W cm), optical transparency (>85% from 400-1800 nm), and moisture-barrier property (water vapor transmission rate = 6.3 × 10(-6) g m(-2) day(-1)). PMID:23386315

  4. Cytokines and the Skin Barrier

    Directory of Open Access Journals (Sweden)

    Jens Malte Baron

    2013-03-01

    Full Text Available The skin is the largest organ of the human body and builds a barrier to protect us from the harmful environment and also from unregulated loss of water. Keratinocytes form the skin barrier by undergoing a highly complex differentiation process that involves changing their morphology and structural integrity, a process referred to as cornification. Alterations in the epidermal cornification process affect the formation of the skin barrier. Typically, this results in a disturbed barrier, which allows the entry of substances into the skin that are immunologically reactive. This contributes to and promotes inflammatory processes in the skin but also affects other organs. In many common skin diseases, including atopic dermatitis and psoriasis, a defect in the formation of the skin barrier is observed. In these diseases the cytokine composition within the skin is different compared to normal human skin. This is the result of resident skin cells that produce cytokines, but also because additional immune cells are recruited. Many of the cytokines found in defective skin are able to influence various processes of differentiation and cornification. Here we summarize the current knowledge on cytokines and their functions in healthy skin and their contributions to inflammatory skin diseases.

  5. Penetration through the Skin Barrier.

    Science.gov (United States)

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

    2016-01-01

    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. During recent decades, the latter has received increased attention as a route for intentionally delivering drugs to patients. This has stimulated research in methods for sampling, measuring and predicting percutaneous penetration. Previous chapters have described how different endogenous, genetic and exogenous factors may affect barrier characteristics. The present chapter introduces the theory for barrier penetration (Fick's law), and describes and discusses different methods for measuring the kinetics of percutaneous penetration of chemicals, including in vitro methods (static and flow-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 penetration. Finally, a short discussion of the advantages and challenges of each method is provided, which will hopefully allow the reader to improve decision making and treatment planning, as well as the evaluation of experimental studies of percutaneous penetration of chemicals. PMID:26844902

  6. Cylindrical air flow reversal barrier

    Energy Technology Data Exchange (ETDEWEB)

    Woznica, C.; Rodziewicz, M.

    1988-06-01

    Describes an innovative design introduced in the ZMP mine in Zory for quick reversal of ventilation air flow. Geologic mining conditions at the 705 m deep horizon, where the barrier was built, are described. According to the design used until now, a reversal system consisted of safety barriers, ventilation air locks, a ventilation bridge and stopping needed in case of a fire when air flow direction must be reversed. Nine air locks and an expensive concrete ventilation bridge were needed and the air locks had to be operated at 8 points of the region to effect reversal. The new design consists of a 2-storey cylindrical barrier which also fulfills the function of a ventilation bridge. It can be manually or remotely operated by a mechanical or pneumatic system. Tests showed that the new barrier permits immediate air flow reversal while retaining 60% of the original air, which is important in the case of fire and methane hazards. It permits improved seam panelling and splitting of pillars and brings an economy of about 40 million zlotys in construction cost. Design and operation of the barrier is illustrated and ventilation air circulation is explained. 7 figs.

  7. Improvement of barrier properties of rotomolded PE containers with nanoclay

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidi, Shadi; Sundararaj, Uttandaraman, E-mail: u.sundararaj@ucalgary.ca [Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada)

    2015-05-22

    Polyethylene (PE) is widely used to make bulk containers in rotational molding process. The challenge in this study is to improve permeation resistance of PE to hydrocarbon solvents and gases. Adding organomodified clay improves the thermal, barrier and mechanical properties of PE. In fact, clay layers create a tortuous path against the permeant, yielding better barrier properties. Due to the non-polar hydrophobic nature of PE and polar hydrophilic structure of clay minerals, the compatibilizer plays a crucial role to enhance the dispersion level of clay in the matrix. In this study High Density Polyethylene (HDPE) and Linear Low Density Polyethylene (LLDPE) layered silicate nanocomposite were melt-compounded with two concentrations of organomodified clay (2 and 4 wt. %). The interaction between nanoclay, compatibilizer and rotomolding grade of PE were examined by using X-ray diffraction, transmission electron microscopy (TEM) and rheology test. Rheology was used to determine the performance of our material at low shear processing condition.

  8. Correlated barrier hopping of CuO nanoparticles

    Science.gov (United States)

    Koshy, Jiji; Soosen, Samuel. M.; Chandran, Anoop; George, K. C.

    2015-12-01

    The ac conduction mechanism in copper oxide nanoparticles with 8 nm size, synthesized by a precipitation method was studied by analyzing ac conductivity in the frequency range of 50 Hz-1 MHz and in the temperature range of 373-573 K. X-ray diffraction and transmission electron microscopy (TEM) were employed for the structural and morphological characterization of CuO nanoparticles. The experimental and theoretical investigations suggested that the ac conduction mechanism in CuO nanoparticles can be successfully explained by a correlated barrier hopping model, which provided reasonable values for the maximum barrier height and characteristic relaxation time. It was also found that bipolaron hopping become prominent up to a particular temperature and beyond that single polaron hopping predominates. Physical parameters such as hopping distance and density of defect states were also calculated. Photoluminescence studies confirm the presence of a surface defect in CuO nanoparticles.

  9. 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.

  10. Transformer coupling for transmitting direct current through a barrier

    Science.gov (United States)

    Brown, Ralph L.; Guilford, Richard P.; Stichman, John H.

    1988-01-01

    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.

  11. Superluminal transmission is possible from now on

    CERN Document Server

    Nowacki, Z A

    2002-01-01

    It is known that superluminal transmission of information and energy contradicts Einstein's relativity. Here we announce an unusual TOE called 'nature theory' in which impossible things become possible. We present the scheme of an apparatus for sending signals over arbitrarily large distances with speeds arbitrarily exceeding the light speed in vacuum. Introducing the notions of effective speed and reliability of superluminal devices, we encourage experimenters to set and break world records in this new branch. At the same time we outline a mechanism (termed 'particle encapsulation') owing to which nature theory remains Lorentz invariant and so consistent with experiments. From among other numerous applications of nature theory we discuss briefly local antigravitation and new computing machines, called 'vacuum computers', applying 'cat principle'. They are of great interest because should enable humans to overcome the Goedel-Turing barrier.

  12. Evaluation of diffusion barrier and electrical properties of tantalum oxynitride thin films for silver metallization

    International Nuclear Information System (INIS)

    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

  13. Application of transmission electron tomography for modeling the renal corpuscle.

    Science.gov (United States)

    Cheng, Delfine; Shen, Sylvie; Chen, Xin-Ming; Pollock, Carol; Braet, Filip

    2013-11-01

    Structural alteration to the microanatomical organization of the glomerular filtration barrier results in proteinuria. Conventional transmission electron microscopy is an important diagnostic tool to assess the degree of ultrastructural damage of the corpusclar filtration unit. However, this approach lacks the ability to collect accurate stereological insights in a relative large tissue volume. Transmission electron tomography offers the ability to gather three-dimensional information with relative ease. Therefore, this contribution aims to highlight what electron tomography can bring to the pathologist in this challenging area of diagnostic practice. Kidney tissue was prepared for routine ultrastructural transmission electron microscopy investigation. Three-dimensional data stacks were automatically acquired by tilting semi-thin sections of 270 nm in an angular range of typically -60° to +60° with 1° increment. Subsequently, models of the filtration unit were produced by computer-assisted tracking of structures of interest. This short report illustrates the capability that transmission electron tomography can offer in the fine structure-function assessment of the porous fenestrated glomerular capillary endothelium, the underlying basement membrane and the podocyte filtration slits. Furthermore, this approach allows the generation of morphometric data about size, shape and volume alterations of the kidney's filtration barrier at the nanoscale.

  14. 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

  15. Reinforcing Power Grid Transmission with FACTS Devices

    CERN Document Server

    Frolov, Vladimir; Chertkov, Misha

    2013-01-01

    We explore optimization methods for planning the placement, sizing and operations of Flexible Alternating Current Transmission System (FACTS) devices installed into the grid to relieve congestion created by load growth or fluctuations of intermittent renewable generation. We limit our selection of FACTS devices to those that can be represented by modification of the inductance of the transmission lines. Our master optimization problem minimizes the $l_1$ norm of the FACTS-associated inductance correction subject to constraints enforcing that no line of the system exceeds its thermal limit. We develop off-line heuristics that reduce this non-convex optimization to a succession of Linear Programs (LP) where at each step the constraints are linearized analytically around the current operating point. The algorithm is accelerated further with a version of the cutting plane method greatly reducing the number of active constraints during the optimization, while checking feasibility of the non-active constraints post...

  16. 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.

  17. Recent key technical barriers in solid oxide fuel cell technology

    Directory of Open Access Journals (Sweden)

    Milewski Jarosław

    2014-03-01

    Full Text Available High-temperature solid oxide fuel cells (SOFCs are considered as suitable components of future large-scale clean and efficient power generation systems. However, at its current stage of development some technical barriers exists which limit SOFC’s potential for rapid large-scale deployment. The present article aims at providing solutions to key technical barriers in SOFC technology. The focus is on the solutions addressing thermal resistance, fuel reforming, energy conversion efficiency, materials, design, and fuel utilisation issues.

  18. 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.

  19. ELECTROSTATICALLY ENHANCED BARRIER FILTER COLLECTION

    Energy Technology Data Exchange (ETDEWEB)

    John Erjavec; Michael D. Mann; Ryan Z. Knutson; Michael L. Swanson; Michael E. Collings

    2003-06-01

    electrostatically enhanced barrier filter collection (EBFC). This concept combines electrostatic precipitation (ESP) with candle filters in a single unit. Similar technology has been recently proven on a commercial scale for atmospheric applications, but needed to be tested at high temperatures and pressures. The synergy obtained by combining the two control technologies into a single system should actually reduce filter system capital and operating costs and make the system more reliable. More specifically, the ESP is expected to significantly reduce candle filter load and also to limit ash reintrainment, allowing for full recovery of baseline pressure drop during backpulsing of the filters.

  20. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    S V S Sastry; S Santra

    2000-06-01

    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 reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable effects on the fusion excitation function. However, a simultaneous analysis of the fusion, elastic and quasi-elastic channels would fix the structure and the reaction unambiguously

  1. PROMOTION, SWITCHING BARRIERS, AND LOYALTY

    Directory of Open Access Journals (Sweden)

    Gu-Shin Tung

    2011-06-01

    Full Text Available This paper investigates the causal relationships among promotion effects, switching barriers, and loyalty in the department stores. The relationship between switching barriers and loyalty reveals partially the same results as the switching barriers theory of Jones et al. (2000. The reasons arise from “too often” and “too similar” sales promotion programs of competitive department stores in Taiwan, leading the promotion effects to not contribute to the attractiveness of competitors. The promotion effects have a positive and significant influence on loyalty, which is consistent with the prior literature. Promotion effects are also the most important weight to loyalty in our tested model but it reveals a seeming loyalty, because the loyalty depends on the reward of promotion. The negative relationship between promotion effects and attractiveness of alternative supports the promotion effects, which can lower the attractiveness of competitors, but these similar promotion plans are not attributed to interpersonal relationships.

  2. Compartmentalized coculture of rat brain endothelial cells and astrocytes: a syngenic model to study the blood-brain barrier.

    Science.gov (United States)

    Demeuse, Ph; Kerkhofs, A; Struys-Ponsar, C; Knoops, B; Remacle, C; van den Bosch de Aguilar, Ph

    2002-11-15

    The specific structure of the blood-brain barrier (BBB) is based on the partnership of brain endothelial cells and astrocytes. In the last decade, cocultures of these two cell types have been developed as in vitro models. However, these studies did not allow close contacts between both cell types. We report here a syngenic coculture model using rat endothelial cells on one side of a polyethylene terephtalate filter and rat astrocytes on the other. Endothelial cells retain their typical morphology and are factor VIII and OX 26 positive. We optimized the diameter of the membrane pores to establish very close contacts between the cells through the membrane pores without mixing the two cell types. Transmission electron microscopy showed evidence of tight junction formation between the endothelial cells and few pinocytic vesicles. The cocultures reached high electrical resistances up to 1000 Omegacm(2) showing their ability to limit the passage of ions. A 15-fold increase in gamma-glutamyl transpeptidase activity was measured in the endothelial cells in coculture compared to endothelial cell monoculture. Our syngenic coculture represents a useful in vitro model of the rat BBB that may prove to be valuable for studying the passage of substances across the barrier as well as other aspects of the BBB function. PMID:12393158

  3. Hepatitis C Transmission after Prostate Biopsy

    Directory of Open Access Journals (Sweden)

    Karim Ferhi

    2013-01-01

    Full Text Available Prostate biopsy is a current and well-codified procedure; antibiotic prophylaxis and rectal enema limit the risk of infection. To date, there has been no reported viral transmission between patients due to a contaminated ultrasound probe. In this study, we report the case of a patient who contracted the hepatitis C virus after transrectal prostate biopsy as part of an individual screening for prostate cancer.

  4. Ideal MHD stability of double transport barrier plasmas in DIII-D

    Science.gov (United States)

    Li, G. Q.; Wang, S. J.; Lao, L. L.; Turnbull, A. D.; Chu, M. S.; Brennan, D. P.; Groebner, R. J.; Zhao, L.

    2008-01-01

    The ideal MHD stability for double transport barrier (DTB or DB) plasmas with varying edge and internal barrier width and height was investigated, using the ideal MHD stability code GATO. A moderate ratio of edge transport barriers (ETB) height to internal transport barriers (ITBs) height is found to be beneficial to MHD stability and the βN is limited by global low n instabilities. For moderate ITB width DB plasmas, if the ETB is weak, the stability is limited by n = 1 (n is the toroidal mode number) global mode; whereas if the ETB is strong it is limited by intermediate-n edge peeling-ballooning modes. Broadening the ITB can improve stability if the ITB half width wi lsim 0.3. For very broad ITB width plasmas the stability is limited by stability to a low n (n > 1) global mode.

  5. Simulation Tool for Dielectric Barrier Discharge Plasma Actuators at Atmospheric and Sub-Atmospheric Pressures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Traditional approaches for active flow separation control using dielectric barrier discharge (DBD) plasma actuators are limited to relatively low-speed flows and...

  6. 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.; Gunapala, Sarath D.

    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.

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

    Science.gov (United States)

    Yuen, Courtney M; Kammerer, J Steve; Marks, Kala; Navin, Thomas R; France, Anne Marie

    2016-01-01

    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.

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

    Science.gov (United States)

    Yuen, Courtney M; Kammerer, J Steve; Marks, Kala; Navin, Thomas R; France, Anne Marie

    2016-01-01

    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. PMID:27082644

  9. Barriers to Leisure-Time Physical Activities in Individuals with Spinal Cord Injury.

    Science.gov (United States)

    Hwang, Eric J; Groves, Mary D; Sanchez, Jacqueline N; Hudson, Cassandra E; Jao, Rachel G; Kroll, Meghan E

    2016-07-01

    This study investigated the personal, environmental, and activity barriers to leisure-time physical activities (LTPAs) among individuals with spinal cord injury (SCI). A survey instrument was administered to 85 participants with SCI. Personal barriers to LTPAs included issues involving motivation, pain, scheduling, and financial resources. Environmental barriers marked the issues regarding availability and accessibility to specialized programs, activities, and professional services. Activity barriers included limitations in equipment, training, and personal skills required by the selected activities. Significant negative correlations were found between these barriers and the levels of physical activity and satisfaction with physical activity. While working with clients with SCI, occupational therapists should identify those LTPA barriers and possible solutions in order to establish individualized action plans for enhancing participation in LTPAs. PMID:27218889

  10. The Solution to Green Barrier

    Institute of Scientific and Technical Information of China (English)

    Cui Yan

    2009-01-01

    @@ The recovery process of world economy is rough and full of twists and turns.Especially the trade protectionism,having reemerged under the mask of"green barrier",is making a great impact on the slowly recovering world economy and trade.Then,what are the characteristics of trade barriers in the post-crisis era?Where is the outlet of Chinese manufacturing industry?With these questions,ourreporter interviewed Professor Zhou Shijian,Standing Director to China Association of International Trade and Senior Researcher to SINO-US Relationship Research Centre of Tsinghua University.

  11. Reactive barriers for 137Cs retention.

    Science.gov (United States)

    Krumhansl, J L; Brady, P V; Anderson, H L

    2001-02-01

    137Cs was dispersed globally by cold war activities and, more recently, by the Chernobyl accident. Engineered extraction of 137Cs from soils and groundwaters is exceedingly difficult. Because the half-life of 137Cs is only 30.2 years, remediation might be more effective (and less costly) if 137Cs 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 135Cs (half-life 2.3 x 10(6) years) in addition to 137Cs. 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 desorption 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 LiNO3 and LiCl washes. Washed clays 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-Ill 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 Cs-doped for 110 days and subjected to an extreme and prolonged rinsing process. All the clays exhibited some capacity for irreversible Cs uptake. However, the residual loading was greatest on K-Mbt (approximately 0.33 wt.% Cs). Thus, this clay would be the optimal material for constructing artifical reactive barriers.

  12. Stacking fault induced tunnel barrier in platelet graphite nanofiber

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Yann-Wen, E-mail: chiidong@phys.sinica.edu.tw, E-mail: ywlan@phys.sinica.edu.tw; Chang, Yuan-Chih; Chang, Chia-Seng; Chen, Chii-Dong, E-mail: chiidong@phys.sinica.edu.tw, E-mail: ywlan@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Chang, Wen-Hao [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi 62102, Taiwan (China); Li, Yuan-Yao [Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi 62102, Taiwan (China)

    2014-09-08

    A correlation study using image inspection and electrical characterization of platelet graphite nanofiber devices is conducted. Close transmission electron microscopy and diffraction pattern inspection reveal layers with inflection angles appearing in otherwise perfectly stacked graphene platelets, separating nanofibers into two domains. Electrical measurement gives a stability diagram consisting of alternating small-large Coulomb blockade diamonds, suggesting that there are two charging islands coupled together through a tunnel junction. Based on these two findings, we propose that a stacking fault can behave as a tunnel barrier for conducting electrons and is responsible for the observed double-island single electron transistor characteristics.

  13. Metamaterial Polarization Converter Analysis: Limits of Performance

    OpenAIRE

    Markovich, Dmitry L.; Andryieuski, Andrei; Zalkovskij, Maksim; Malureanu, Radu; Lavrinenko, Andrei V.

    2012-01-01

    In this paper we analyze the theoretical limits of a metamaterial converter that allows for linear-to- elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed level of the design generalization. Our analysis reveals that the maximal conversion e?ciency for transmission through a single metamaterial layer is 50%, while the realistic re ection con?guration can give the conversion e?ciency up to 90%....

  14. Wideband Analog Transmission System Based on the External Intensity Electro-Optic Modulator

    Directory of Open Access Journals (Sweden)

    Jiri Svarny

    2016-01-01

    Full Text Available The work deals with design and integration of an analog electro-optic transmission system suitable for some specialized tasks of diagnostics and measurements. The system is based on principle of external intensity modulation of fiber guided laser radiation. Besides wideband and almost lossless transmission the system tolerates extreme length of the transmitting medium and ensures ultimate galvanic barrier between the input and output.

  15. 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 da

  16. Systems study on engineered barriers: barrier performance analysis

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. Quantum Contact Transmission

    Institute of Scientific and Technical Information of China (English)

    崔迪

    2015-01-01

    Abstract:Quantum transmission is based on quantum entanglement, which is a kind of the phenomenon of quantum mechanics. Quantum object refers to two or more between the localized, the classic strong correlation. When two object quantum entanglement in the quantum state is not independent, but related, and the correlation distance, a pair of electronic of entanglement state, no matter how far apart, they spin direction will remain an up and a down. If one of the electronic spin direction is changed, another of the electron spin direction wil follow to change immediately.

  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. Representing solute transport through the multi-barrier disposal system by simplified concepts

    Energy Technology Data Exchange (ETDEWEB)

    Poteri, A.; Nordman, H.; Pulkkanen, V-M. [VTT Technical Research Centre of Finland, Espoo (Finland); Kekaelaeinen, P. [Jyvaeskylae Univ. (Finland). Dept. pf Physics; Hautojaervi, A.

    2012-02-15

    The repository system chosen in Finland for spent nuclear fuel is composed of multiple successive transport barriers. If a waste canister is leaking, this multi-barrier system retards and limits the release rates of radionuclides into the biosphere. Analysis of radionuclide migration in the previous performance assessments has largely been based on numerical modelling of the repository system. The simplified analytical approach introduced here provides a tool to analyse the performance of the whole system using simplified representations of the individual transport barriers. This approach is based on the main characteristics of the individual barriers and on the generic nature of the coupling between successive barriers. In the case of underground repository the mass transfer between successive transport barriers is strongly restricted by the interfaces between barriers leading to well-mixed conditions in these barriers. The approach here simplifies the barrier system so that it can be described with a very simple compartment model, where each barrier is represented by a single, or in the case of buffer, by not more than two compartments. This system of compartments could be solved in analogy with a radioactive decay chain. The model of well mixed compartments lends itself to a very descriptive way to represent and analyse the barrier system because the relative efficiency of the different barriers in hindering transport of solutes can be parameterised by the solutes half-times in the corresponding compartments. In a real repository system there will also be a delay between the start of the inflow and the start of the outflow from the barrier. This delay can be important for the release rates of the short lived and sorbing radionuclides, and it was also included in the simplified representation of the barrier system. In a geological multi-barrier system, spreading of the outflowing release pulse is often governed by the typical behaviour of one transport barrier

  1. Diamond and Diamond-Like Materials as Hydrogen Isotope Barriers

    International Nuclear Information System (INIS)

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project was to develop diamond and diamond-like thin-films as hydrogen isotope permeation barriers. Hydrogen embrittlement limits the life of boost systems which otherwise might be increased to 25 years with a successful non-reactive barrier. Applications in tritium processing such as bottle filling processes, tritium recovery processes, and target filling processes could benefit from an effective barrier. Diamond-like films used for low permeability shells for ICF and HEDP targets were also investigated. Unacceptable high permeabilities for hydrogen were obtained for plasma-CVD diamond-like-carbon films

  2. The Born transmission eigenvalue problem

    Science.gov (United States)

    Cakoni, Fioralba; Colton, David; Rezac, Jacob D.

    2016-10-01

    In this paper we study the distribution of transmission eigenvalues in the complex plane for obstacles whose contrast is small in magnitude. We use a first order approximation of the refractive index to derive and study an approximate interior transmission problem. In the case of spherically stratified media, we prove existence and discreteness of transmission eigenvalues and derive a condition under which the complex part of transmission eigenvalues cannot lie in a strip parallel to the real axis. For obstacles with general shape, we demonstrate that if transmission eigenvalues exist then they form a discrete set.

  3. Transmission Properties of Fiber Probes

    Institute of Scientific and Technical Information of China (English)

    XUE Chun-rong; ZHU Sheng-xiang; XIAO Zhi-gang

    2004-01-01

    Transmission properties of tapered fiber including right cone fiber and bend optical fiber are discussed. The transmission efficiency of the tapered fiber is measured. The curve of transmission efficiency versus taper cone angle is given. By the scalar wave equation and Gaussian approximation, transmission properties of the two kinds of tapered fibers are analyzed, the power losses caused by taper cone angle and by the bending are also calculated. From the experiments and theoretical analysis, it could come to a conclusion that the wider the taper cone angle is, the higher the transmission efficiency will be.

  4. Intestinal barrier homeostasis in inflammatory bowel disease.

    Science.gov (United States)

    Goll, Rasmus; van Beelen Granlund, Atle

    2015-01-01

    The single-cell thick intestinal epithelial cell (IEC) lining with its protective layer of mucus is the primary barrier protecting the organism from the harsh environment of the intestinal lumen. Today it is clear that the balancing act necessary to maintain intestinal homeostasis is dependent on the coordinated action of all cell types of the IEC, and that there are no passive bystanders to gut immunity solely acting as absorptive or regenerative cells: Mucin and antimicrobial peptides on the epithelial surface are continually being replenished by goblet and Paneth's cells. Luminal antigens are being sensed by pattern recognition receptors on the enterocytes. The enteroendocrine cells sense the environment and coordinate the intestinal function by releasing neuropeptides acting both on IEC and inflammatory cells. All this while cells are continuously and rapidly being regenerated from a limited number of stem cells close to the intestinal crypt base. This review seeks to describe the cell types and structures of the intestinal epithelial barrier supporting intestinal homeostasis, and how disturbance in these systems might relate to inflammatory bowel disease.

  5. Development of dual-band barrier detectors

    Science.gov (United States)

    Plis, Elena; Myers, Stephen A.; Ramirez, David A.; Krishna, Sanjay

    2016-05-01

    We report on the development of dual-band InAs/GaSb type-II strained layer superlattices (T2SL) detectors with barrier designs at SK Infrared. Over the past five years, we demonstrated mid-wave/long-wave (MW/LWIR, cut-off wavelengths are 5 μm and 10.0 μm), and LW/LWIR (cut-off wavelengths are 9 μm and 11.0 μm) detectors with nBn and pBp designs. Recent results include a high performance bias-selectable long/long-wavelength infrared photodetector based on T2SL with a pBp barrier architecture. The two channels 50% cut-off wavelengths were ~ 9.2 μm and ~ 12 μm at 77 K. The "blue" and "red" LWIR absorbers demonstrated saturated QE values of 34 % and 28 %, respectively, measured in a backside illuminated configuration with a ~ 35 μm thick layer of residual GaSb substrate. Bulk-limited dark current levels were ~ 2.6 x 10-7 A/cm2 at + 100 mV and ~ 8.3 x 10-4 A/cm2 at - 200 mV for the "blue" and "red" channels, respectively.

  6. THE TOURISM BARRIERS OF THE DISABLED

    Directory of Open Access Journals (Sweden)

    Nagy Andreea

    2011-07-01

    Full Text Available This article seeks to address a very sensitive issue in Romania, the disabled tourism. The natural question is whether tourism can respond and meet the needs of such people. Internationally, the researches in detail about tourism for people with disabilities are limited in this direction, and those who exist are focused more on lack of physical access to certain services in the hotel units.-As for the problems (barriers that a person with disabilities may face when seeking to participate in the act of travel there were found numerous internal and external barriers in trying to participate in tourism activities-The study seeks to identify how normal people behave towards people with disabilities and aims to demonstrate the existence of correlations between the responses of the interviewees, which would lead to the presentation as close to the truth as possible of the results from the sample (section, transposed over the population from which the sample belongs and also lead to finding conclusions on which there could be made several proposals.

  7. Architectural Barriers Removal: Resource Guide.

    Science.gov (United States)

    Office of Human Development (DHEW), Washington, DC. Office for Handicapped Individuals.

    The guide presents information on resources for eliminating architectural barriers for handicapped persons. Entries are grouped according to information resources, funding sources, and publications available from the federal government. Seven organizations are described in terms of agency goals, publications, and materials. Federal programs…

  8. The blood-brain barrier.

    Science.gov (United States)

    Obermeier, Birgit; Verma, Ajay; Ransohoff, Richard M

    2016-01-01

    In autoimmune neurologic disorders, the blood-brain barrier (BBB) plays a central role in immunopathogenesis, since this vascular interface is an entry path for cells and effector molecules of the peripheral immune system to reach the target organ, the central nervous system (CNS). The BBB's unique anatomic structure and the tightly regulated interplay of its cellular and acellular components allow for maintenance of brain homeostasis, regulation of influx and efflux, and protection from harm; these ensure an optimal environment for the neuronal network to function properly. In both health and disease, the BBB acts as mediator between the periphery and the CNS. For example, immune cell trafficking through the cerebral vasculature is essential to clear microbes or cell debris from neural tissues, while poorly regulated cellular transmigration can underlie or worsen CNS pathology. In this chapter, we focus on the specialized multicellular structure and function of the BBB/neurovascular unit and discuss how BBB breakdown can precede or be a consequence of neuroinflammation. We introduce the blood-cerebrospinal fluid barrier and include a brief aside about evolutionary aspects of barrier formation and refinements. Lastly, since restoration of barrier function is considered key to ameliorate neurologic disease, we speculate about new therapeutic avenues to repair a damaged BBB. PMID:27112670

  9. Injectable barriers for waste isolation

    International Nuclear Information System (INIS)

    In this paper the authors report laboratory work and numerical simulation done in support of development and demonstration of injectable barriers formed from either of two fluids: colloidal silica or polysiloxane. Two principal problems addressed here are control of gel time and control of plume emplacement in the vadose zone. Gel time must be controlled so that the viscosity of the barrier fluid remains low long enough to inject the barrier, but increases soon enough to gel the barrier in place. During injection, the viscosity must be low enough to avoid high injection pressures which could uplift or fracture the formation. To test the grout gel time in the soil, the injection pressure was monitored as grouts were injected into sandpacks. When grout is injected into the vadose zone, it slumps under the influence of gravity, and redistributes due to capillary forces as it gels. The authors have developed a new module for the reservoir simulator TOUGH2 to model grout injection into the vadose zone, taking into account the increase of liquid viscosity as a function of gel concentration and time. They have also developed a model to calculate soil properties after complete solidification of the grout. The numerical model has been used to design and analyze laboratory experiments and field pilot tests. The authors present the results of computer simulations of grout injection, redistribution, and solidification

  10. Injectable barriers for waste isolation

    Energy Technology Data Exchange (ETDEWEB)

    Persoff, P.; Finsterle, S.; Moridis, G.J.; Apps, J.; Pruess, K. [Lawrence Berkeley National Lab., CA (United States). Earth Sciences Div.; Muller, S.J. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

    1995-03-01

    In this paper the authors report laboratory work and numerical simulation done in support of development and demonstration of injectable barriers formed from either of two fluids: colloidal silica or polysiloxane. Two principal problems addressed here are control of gel time and control of plume emplacement in the vadose zone. Gel time must be controlled so that the viscosity of the barrier fluid remains low long enough to inject the barrier, but increases soon enough to gel the barrier in place. During injection, the viscosity must be low enough to avoid high injection pressures which could uplift or fracture the formation. To test the grout gel time in the soil, the injection pressure was monitored as grouts were injected into sandpacks. When grout is injected into the vadose zone, it slumps under the influence of gravity, and redistributes due to capillary forces as it gels. The authors have developed a new module for the reservoir simulator TOUGH2 to model grout injection into the vadose zone, taking into account the increase of liquid viscosity as a function of gel concentration and time. They have also developed a model to calculate soil properties after complete solidification of the grout. The numerical model has been used to design and analyze laboratory experiments and field pilot tests. The authors present the results of computer simulations of grout injection, redistribution, and solidification.

  11. Overcoming Barriers: Women in Superintendency

    Science.gov (United States)

    Miller, Claire M.

    2009-01-01

    Women currently represent the largest number of teachers in the United States but remain underrepresented in the superintendent position. This suggests that the superintendency has been influenced by patriarchy. If women are to break through the barriers that prevent them from attaining a superintendency, we will need to understand the social…

  12. Communities Address Barriers to Connectivity.

    Science.gov (United States)

    Byers, Anne

    1996-01-01

    Rural areas lag behind urban areas in access to information technologies. Public institutions play a critical role in extending the benefits of information technologies to those who would not otherwise have access. The most successful rural telecommunications plans address barriers to use, such as unawareness of the benefits, technophobia, the…

  13. Community-based approaches for prevention of mother to child transmission in resource-poor settings: a social ecological review

    Directory of Open Access Journals (Sweden)

    Leila Katirayi

    2012-07-01

    Full Text Available Introduction: Numerous barriers to optimal uptake of prevention of mother to child transmission (PMTCT services occur at community level (i.e., outside the healthcare setting. To achieve elimination of paediatric HIV, therefore, interventions must also work within communities to address these barriers and increase service use and need to be informed by evidence. This paper reviews community-based approaches that have been used in resource-limited settings to increase rates of PMTCT enrolment, retention in care and successful treatment outcomes. It aims to identify which interventions work, why they may do so and what knowledge gaps remain. Methods: First, we identified barriers to PMTCT that originate outside the health system. These were used to construct a social ecological framework categorizing barriers to PMTCT into the following levels of influence: individual, peer and family, community and sociocultural. We then used this conceptual framework to guide a review of the literature on community-based approaches, defined as interventions delivered outside of formal health settings, with the goal of increasing uptake, retention, adherence and positive psychosocial outcomes in PMTCT programmes in resource-poor countries. Results: Our review found evidence of effectiveness of strategies targeting individuals and peer/family levels (e.g., providing household HIV testing and training peer counsellors to support exclusive breastfeeding and at community level (e.g., participatory women's groups and home-based care to support adherence and retention. Evidence is more limited for complex interventions combining multiple strategies across different ecological levels. There is often little information describing implementation; and approaches such as “community mobilization” remain poorly defined. Conclusions: Evidence from existing community approaches can be adapted for use in planning PMTCT. However, for successful replication of evidence

  14. Electric Field Control of the Resistance of Multiferroic Tunnel Junctions with Magnetoelectric Antiferromagnetic Barriers

    Science.gov (United States)

    Merodio, P.; Kalitsov, A.; Chshiev, M.; Velev, J.

    2016-06-01

    Based on model calculations, we predict a magnetoelectric tunneling electroresistance effect in multiferroic tunnel junctions consisting of ferromagnetic electrodes and magnetoelectric antiferromagnetic barriers. Switching of the antiferromagnetic order parameter in the barrier in applied electric field by means of the magnetoelectric coupling leads to a substantial change of the resistance of the junction. The effect is explained in terms of the switching of the orientations of local magnetizations at the barrier interfaces affecting the spin-dependent interface transmission probabilities. Magnetoelectric multiferroic materials with finite ferroelectric polarization exhibit an enhanced resistive change due to polarization-induced spin-dependent screening. These results suggest that devices with active barriers based on single-phase magnetoelectric antiferromagnets represent an alternative nonvolatile memory concept.

  15. Transport Properties of Two-Dimensional Electron Gases in Antiparallel Magnetic-Electric Barrier Structures

    Institute of Scientific and Technical Information of China (English)

    PING Yun-Xia; CHENG Ze

    2006-01-01

    We study theoretically transport properties of two-dimensional electron gases through antiparallel magnetic electric barrier structures. Two kinds of magnetic barrier configurations are employed: one is that the strength of the double δ-function in opposite directions is equal and the other is that the strength is unequal. Similarities and differences of electronic transports are presented. It is found that the transmission and the conductance depend strongly on the shape of the magnetic barrier and the height of the electric barrier. The results indicate that this system does not possess any spin filtering and spin polarization and electron gases can realize perfect resonant tunneling and wave-vector filtering properties. Moreover, the strength of the effect of the inhomogeneous magnetic field on the transport properties is discussed.

  16. Blood–brain barrier: a real obstacle for therapeutics

    Directory of Open Access Journals (Sweden)

    Shiekh FA

    2012-07-01

    Full Text Available Farooq A ShiekhAix-Marseille Université, URMITE, UMR, CNRS 7278, IRD 198, Marseille, FranceIn a recent report published in the International Journal of Nanomedicine, Gulati et al1 have described the most innovative study addressing an important issue of the "blood–brain barrier," which can act as a barrier to one of the fundamental goals of modern neurobiology that would have a direct impact on highly debated future therapeutics for both brain cancer and neurological disorders. Contrary to what has been the case with conventional therapy, the authors were able to completely bypass the blood–brain barrier (Figure 1 – a limiting factor for efficient drug delivery – by proposing a new, alternative approach using nanoengineered TNT/Ti implants for local delivery of chemotherapeutics such as doxorubicin into the brain. There must be millions of good drugs sitting in pharmaceutical company stores that cannot be delivered simply because they cannot get past the blood–brain barrier.2 This is an area that has been under-researched and its significance has not yet been recognized. Neuroscience textbooks bury this issue in the appendix, PhD programs give it a cursory treatment, and pharmaceutical companies have tried to ignore it. Despite the blood–brain barrier acting as a stubbornly real obstacle for potential drugs to be used against many disorders of the central nervous system, the field of drug delivery is advancing rapidly. View original paper by Gulati and colleagues.

  17. Submerged Barriers in the Ni(+) Assisted Decomposition of Propionaldehyde.

    Science.gov (United States)

    Mansell, A; Theis, Z; Gutierrez, M G; Faza, O Nieto; Lopez, C Silva; Bellert, D J

    2016-04-21

    The reaction dynamics of the Ni(+) mediated decarbonylation of propionaldehyde was assessed using the single photon initiated decomposition rearrangement reaction (SPIDRR) technique. The exothermic production of Ni(+)CO was temporally monitored and the associated rate constants, k(E), were extracted as a function of activating photon energy. In addition, the reaction potential energy surface was calculated at the UCCSD(T)/def2-TZVP//PBEPBE/cc-pVDZ level of theory to provide an atomistic description of the reaction profile. The decarbonylation of propionaldehyde can be understood as proceeding through parallel competitive reaction pathways that are initiated by Ni(+) insertion into either the C-C or C-H bond of the propionaldehyde carbonyl carbon. Both paths lead to the elimination of neutral ethane and are governed by submerged barriers. The lower energy sequence is a consecutive C-C/C-H addition process with a submerged barrier of 14 350 ± 600 cm(-1). The higher energy sequence is a consecutive C-H/C-C addition process with a submerged barrier of 15 400 ± 600 cm(-1). Both barriers were determined using RRKM calculations fit to the experimentally determined k(E) values. The measured energy difference between the two barriers agrees with the DFT computed difference in rate limiting transition-state energies, 18 413 and 19 495 cm(-1). PMID:27054589

  18. A new alternative in vertical barrier wall construction

    Energy Technology Data Exchange (ETDEWEB)

    Rawl, G.F. [Horizontal Technologies Inc., Matlacha, FL (United States)

    1997-12-31

    A new proprietary vertical barrier wall system has been developed to revolutionize the construction process by eliminating many of the concerns of conventional installation method`s with respect to performance, installation constraints and costs. Vertical barrier walls have been used in the environmental and construction industries for a variety of purposes, usually for cut-off or containment. The typical scenario involves a groundwater contamination problem, in which a vertical barrier wall is utilized to contain or confine the spread of contaminants below the ground surface. Conventional construction techniques have been adequate in many applications, but often fall short of their intended purposes due to physical constraints. In many instances, the economics of these conventional methods have limited the utilization of physical barrier walls. Polywall, the trade name for this new barrier wall technology, was subsequently developed to meet these needs and offer a number of distinct advantages in a variety of scenarios by maximizing confinement and minimizing installation costs. Polywall is constructed from chemically resistant high density polyethylene (HDPE) plastic. It has proven in a half-dozen projects to date to be the most cost-effective and technically sound approach to many containment situations. This paper will cover the development of the technology and will provide a brief synopsis of several installations.

  19. Barriers to drug delivery in solid tumors.

    Science.gov (United States)

    Sriraman, Shravan Kumar; Aryasomayajula, Bhawani; Torchilin, Vladimir P

    2014-01-01

    Over the last decade, significant progress has been made in the field of drug delivery. The advent of engineered nanoparticles has allowed us to circumvent the initial limitations to drug delivery such as pharmacokinetics and solubility. However, in spite of significant advances to tumor targeting, an effective treatment strategy for malignant tumors still remains elusive. Tumors possess distinct physiological features which allow them to resist traditional treatment approaches. This combined with the complexity of the biological system presents significant hurdles to the site-specific delivery of therapeutic drugs. One of the key features of engineered nanoparticles is that these can be tailored to execute specific functions. With this review, we hope to provide the reader with a clear understanding and knowledge of biological barriers and the methods to exploit these characteristics to design multifunctional nanocarriers, effect useful dosing regimens and subsequently improve therapeutic outcomes in the clinic. PMID:25068098

  20. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Jungerstedt, J; Hellgren, Lars; Drachmann, Tue;

    2010-01-01

    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups...... and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically...... significant differences were found between young and old skin for ceramide subgroups or ceramide/cholesterol ratios, and there was no statistically significant correlation between answers about dry skin and ceramide levels. Interestingly, a statistically significant higher ceramide/cholesterol ratio was found...

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

    Directory of Open Access Journals (Sweden)

    Hacker K

    2015-10-01

    Full Text Available Karen Hacker,1,2 Maria Anies,2 Barbara L Folb,2,3 Leah Zallman4–6 1Allegheny County Health Department, Pittsburgh, PA, USA; 2Graduate School of Public Health, 3Health Sciences Library System, University of Pittsburgh, Pittsburgh, PA, USA; 4Institute for Community Health, Cambridge, MA, USA; 5Cambridge Health Alliance, Cambridge, MA, USA; 6Harvard School of Medicine, Boston, MA, USA Abstract: 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

  2. Microstrip transmission line for soil moisture measurement

    Science.gov (United States)

    Chen, Xuemin; Li, Jing; Liang, Renyue; Sun, Yijie; Liu, C. Richard; Rogers, Richard; Claros, German

    2004-12-01

    Pavement life span is often affected by the amount of voids in the base and subgrade soils, especially moisture content in pavement. Most available moisture sensors are based on the capacitive sensing using planar blades. Since the planar sensor blades are fabricated on the same surface to reduce the overall size of the sensor, such structure cannot provide very high accuracy for moisture content measurement. As a consequence, a typical capacitive moisture sensor has an error in the range of 30%. A more accurate measurement is based on the time domain refelctometer (TDR) measurement. However, typical TDR system is fairly expensive equipment, very large in size, and difficult to operate, the moisture content measurement is limited. In this paper, a novel microstrip transmission line based moisture sensor is presented. This sensor uses the phase shift measurement of RF signal going through a transmission line buried in the soil to be measured. Since the amplitude of the transmission measurement is a strong function of the conductivity (loss of the media) and the imaginary part of dielectric constant, and the phase is mainly a strong function of the real part of the dielectric constant, measuring phase shift in transmission mode can directly obtain the soil moisture information. This sensor was designed and implemented. Sensor networking was devised. Both lab and field data show that this sensor is sensitive and accurate.

  3. HIV transmission biology: translation for HIV prevention.

    Science.gov (United States)

    Ronen, Keshet; Sharma, Amit; Overbaugh, Julie

    2015-11-01

    Rigorous testing of new HIV-prevention strategies is a time-consuming and expensive undertaking. Thus, making well informed decisions on which candidate-prevention approaches are most likely to provide the most benefit is critical to appropriately prioritizing clinical testing. In the case of biological interventions, the decision to test a given prevention approach in human trials rests largely on evidence of protection in preclinical studies. The ability of preclinical studies to predict efficacy in humans may depend on how well the model recapitulates key biological features of HIV transmission relevant to the question at hand. Here, we review our current understanding of the biology of HIV transmission based on data from animal models, cell culture, and viral sequence analysis from human infection. We summarize studies of the bottleneck in viral transmission; the characteristics of transmitted viruses; the establishment of infection; and the contribution of cell-free and cell-associated virus. We seek to highlight the implications of HIV-transmission biology for development of prevention interventions, and to discuss the limitations of existing preclinical models. PMID:26418086

  4. Gas transmission pricing

    International Nuclear Information System (INIS)

    The natural gas transmission system consists of facilities that are normally regarded as being a natural monopoly. This is a property the natural gas network share with the telecommunication and the electricity network. All of these networks have, to some degree, been deregulated during the last decades. The deregulation of the natural gas network was in Europe formalized when the gas directive was passed in the European Commission 22 June 1998. This directive opens for third party access to the transportation facilities in the natural gas network. Open network access is important in order to achieve gains from increased competition, and transmission tariffs are important in achieving this. Due to the technical nature of the gas network, several physical and technical threshold values exist. If such values are trespassed, only minor incremental deliveries in on part can cause significant unintended reductions elsewhere. When performing analyses on optimal operation of a natural gas network, it is therefore necessary to take into consideration these properties. In this paper the physical properties of the natural gas flow are modeled by taking into account the design parameters of the pipelines in the system and the effects of pressure difference between the nodes in the network. The connection between pressure difference and gas flow is handled with the Weymouth-equation. A quadratic optimization model is constructed in order to analyze operation of the network. This paper examines how the efficiency of the natural gas market is affected by the operation and pricing of the transmission system. The tariff regimes investigated include fixed fees, nodal pricing, Chao-Peck pricing and zonal pricing. An examination of the existing tariff-regime in the North-Sea will also be performed as well as a comparison with the above mentioned tariff mechanisms. To perform the analyses, an example network will be presented and analyzed. By combining the physical flow calculations

  5. 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

  6. Transmission rights and market power

    International Nuclear Information System (INIS)

    Most of the concerns about physical transmission rights relate to the ability to implicitly or explicitly remove that transmission capacity from the market-place. Under a very strict form of physical right, owners could simply choose not to sell it if they don't want to use it. Modifications that require the release of spare capacity back into an open market could potentially alleviate this problem but there is concern that such releases would not occur far enough in advance to be of much use to schedulers. Similarly, the transmission capacity that is made available for use by non-rights holders can also be manipulated by the owners of transmission rights. The alternative form, financial transmission rights, provide to their owners congestion payments, but physical control of transmission paths. In electricity markets such as California's, even financial transmission rights could potentially be utilized to effectively withhold transmission capacity from the marketplace. However, methods for withholding transmission capacity are somewhat more convoluted, and probably more difficult, for owners of financial rights than for owners of physical rights. In this article, the author discusses some of the potential concerns over transmission rights and their use for the exercise of various forms of market power

  7. Research on Electro-Magnetic Environment of UHV Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Employing even higher voltage level to promote power transmission economy is an important subject in the program of power transmission from west to east. The influence of electro-magnetic environment of transmission project being closely related with human health and construction cost has to be seriously considered before advancing transmission voltage. This paper analyzes and discusses overseas and domestic research achievements on radio interference, audible noise, power frequency electric field, power frequency magnetic fields, DC resultant field intensity and ion stream involved in power transmission at ultra-high-voltage (UHV)AC and ± 800 kV DC or even higher voltage levels. Suggestions on limiting electro-magnetic effects and their ceiling value as well as measures to improve electro-magnetic environment are put forward.

  8. Stress transmission in soil

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    the principle behind the elasticity theory. However, if fitting the Söhne model to stress measurements in all three depths, the stresses were underestimated at 0.3 and 0.6 m depth, and overestimated at 0.9 m depth. A fit of the model based on data only at 0.3 m depth indicated that stresses were transmitted......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...

  9. Fiber optic data transmission

    Science.gov (United States)

    Shreve, Steven T.

    1987-01-01

    The Ohio University Avionics Engineering Center is currently developing a fiber optic data bus transmission and reception system that could eventually replace copper cable connections in airplanes. The original form of the system will transmit information from an encoder to a transponder via a fiber optic cable. An altimeter and an altitude display are connected to a fiber optic transmitter by copper cable. The transmitter converts the altimetry data from nine bit parallel to serial form and send these data through a fiber optic cable to a receiver. The receiver converts the data using a cable similar to that used between the altimeter and display. The transmitting and receiving ends also include a display readout. After completion and ground testing of the data bus, the system will be tested in an airborne environment.

  10. Thrips transmission of tospoviruses.

    Science.gov (United States)

    Rotenberg, Dorith; Jacobson, Alana L; Schneweis, Derek J; Whitfield, Anna E

    2015-12-01

    One hundred years ago, the disease tomato spotted wilt was first described in Australia. Since that time, knowledge of this disease caused by Tomato spotted wilt virus (TSWV) and transmitted by thrips (insects in the order Thysanoptera) has revealed a complex relationship between the virus, vector, plant host, and environment. Numerous tospoviruses and thrips vectors have been described, revealing diversity in plant host range and geographical distributions. Advances in characterization of the tripartite interaction between the virus, vector, and plant host have provided insight into molecular and ecological relationships. Comparison to animal-infecting viruses in the family Bunyaviridae has enabled the identification of commonalities between tospoviruses and other bunyaviruses in transmission by arthropod vectors and molecular interactions with hosts. This review provides a special emphasis on TSWV and Frankliniella occidentalis, the model tospovirus-thrips pathosystem. However, other virus-vector combinations are also of importance and where possible, comparisons are made between different viruses and thrips vectors. PMID:26340723

  11. Ultrasonic wave transducer for high temperature barrier

    International Nuclear Information System (INIS)

    This transducer is made by a metallic body pivoting on a support fixed to the barrier and an internal vitroceramic waveguide in contact on the barrier and on the other end on a piezoelectric ceramic element

  12. Prototype Hanford Surface Barrier: Design basis document

    International Nuclear Information System (INIS)

    The Hanford Site Surface Barrier Development Program (BDP) was organized in 1985 to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site and other arid sites. This document provides the basis of the prototype barrier. Engineers and scientists have momentarily frozen evolving barrier designs and incorporated the latest findings from BDP tasks. The design and construction of the prototype barrier has required that all of the various components of the barrier be brought together into an integrated system. This integration is particularly important because some of the components of the protective barreir have been developed independently of other barreir components. This document serves as the baseline by which future modifications or other barrier designs can be compared. Also, this document contains the minutes of meeting convened during the definitive design process in which critical decisions affecting the prototype barrier's design were made and the construction drawings

  13. Overcoming Barriers to Shared Decision Making

    Science.gov (United States)

    ... team to break it down. Barriers to shared decision making and solutions to overcome them include: Barrier: Fear, anger, stress or other emotions Solution: Strong emotions can interfere with your ability ...

  14. Prioritizing Scientific Data for Transmission

    Science.gov (United States)

    Castano, Rebecca; Anderson, Robert; Estlin, Tara; DeCoste, Dennis; Gaines, Daniel; Mazzoni, Dominic; Fisher, Forest; Judd, Michele

    2004-01-01

    A software system has been developed for prioritizing newly acquired geological data onboard a planetary rover. The system has been designed to enable efficient use of limited communication resources by transmitting the data likely to have the most scientific value. This software operates onboard a rover by analyzing collected data, identifying potential scientific targets, and then using that information to prioritize data for transmission to Earth. Currently, the system is focused on the analysis of acquired images, although the general techniques are applicable to a wide range of data modalities. Image prioritization is performed using two main steps. In the first step, the software detects features of interest from each image. In its current application, the system is focused on visual properties of rocks. Thus, rocks are located in each image and rock properties, such as shape, texture, and albedo, are extracted from the identified rocks. In the second step, the features extracted from a group of images are used to prioritize the images using three different methods: (1) identification of key target signature (finding specific rock features the scientist has identified as important), (2) novelty detection (finding rocks we haven t seen before), and (3) representative rock sampling (finding the most average sample of each rock type). These methods use techniques such as K-means unsupervised clustering and a discrimination-based kernel classifier to rank images based on their interest level.

  15. 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

    are made to share the expenses in transmission derived from their integration, they may see the doors of electricity markets closed for not being competitive enough. This paper presents a model to decide the amount of wind resources that are economically exploitable at a given location from a transmission......-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...

  16. Aquatic polymers can drive pathogen transmission in coastal ecosystems

    OpenAIRE

    Shapiro, Karen; Krusor, Colin; Mazzillo, Fernanda F. M.; Conrad, Patricia A.; Largier, John L.; Jonna A K Mazet; Silver, Mary W.

    2014-01-01

    Gelatinous polymers including extracellular polymeric substances (EPSs) are fundamental to biophysical processes in aquatic habitats, including mediating aggregation processes and functioning as the matrix of biofilms. Yet insight into the impact of these sticky molecules on the environmental transmission of pathogens in the ocean is limited. We used the zoonotic parasite Toxoplasma gondii as a model to evaluate polymer-mediated mechanisms that promote transmission of terrestrially derived pa...

  17. Infectious disease in animal metapopulations: the importance of environmental transmission

    OpenAIRE

    Park, Andrew W.

    2012-01-01

    Motivated by an array of infectious diseases that threaten wildlife populations, a simple metapopulation model (subpopulations connected by animal movement) is developed, which allows for both movement-based and environmental transmission. The model demonstrates that for a range of plausible parameterizations of environmental transmission, increased movement rate of animals between discrete habitats can lead to a decrease in the overall proportion of sites that are occupied. This can limit th...

  18. The use of visual barriers to reduce aggression among a group of marabou storks (Leptoptilos crumeniferus).

    Science.gov (United States)

    Valuska, Annie J; Leighty, Katherine A; Schutz, Paul J; Ferrie, Gina M; Sky, Christy C; Bettinger, Tamara L

    2013-01-01

    Marabou storks are one of the most commonly held birds in zoos, but the captive population faces challenges related to high mortality. One of the most common causes of death among captive marabou storks is conspecific aggression. There is a pressing need to better understand how to manage this aggression. One method that has been used successfully to reduce aggression in other species is the addition of visual barriers to the enclosure, though there are no published studies on their effect on storks. We studied the behavioral changes in a group of 2.2 marabou storks following the addition of two shade cloth barriers to their enclosure; we documented all occurrences of aggressive behavior, as well as time spent proximate to the barriers (or the space between barrier posts, when the shade cloth was removed) and time spent using the barriers to block the view of other storks. The presence of the shade cloth did not change the amount of time storks spent proximate to the barriers, nor did they spend more than 2% of their time using the barriers to block other storks, but the presence of the barriers significantly reduced displacement activity. Barriers may afford captive marabou storks an important means of escaping conflict, as flight-restriction and housing in an enclosure can limit their opportunities to give a signal of retreat or submission. PMID:24105900

  19. Autostereoscopic display concept with time-sequential wavelength-selective filter-barrier

    Science.gov (United States)

    Jurk, Silvio; Kuhlmey, Mathias; Bartmann, Roland; Duckstein, Bernd; de la Barré, René

    2016-03-01

    A spatially multiplexed autostereoscopic 3D display design with a strip barrier consisting of RGB-color filters is presented. The wavelength selective filter barrier emits the light from a display area larger than that of common autostereoscopic barrier displays. However, such construction is still used rather rarely. The time sequential operation mode is a supplemental option. Wavelength selective filter barrier arrangements exhibit characteristics different from common barrier displays with similar barrier pitch and ascent. In particular these constructions show strong angular luminance dependency under barrier inclination specified by correspondent slant angle. In time sequential implementation it is important to avoid that quick eye or eyelid movement lead to visible color artifacts. Those circumstances limit the possibility to find well working and usable display designs superior to usual barrier displays. The newly introduced design is usable as a multi user display as well as a single user system with user adaptive control. In case of tracked single user mode the adaption in x-z-direction is continuously. The design has been modelled with simulation software developed for that purpose. The modelling of wavelength-selective barriers was used to calculate the light ray distribution properties of that arrangement. For the experimental verification of the image separation and evaluation of image quality, commercially available display components were combined for a display demonstrator.

  20. Schottky Barrier with Liquid Metal

    Science.gov (United States)

    Modi, B. P.; Patel, K. D.

    2011-12-01

    Schottky barrier with liquid metal may provide an attractive and new opportunity to look into various aspect of the evolution of Schottky interfaces in a relatively beneficial manner [1]. Here gallium-silicon diode has been fabricated and investigated especially around the melting point of gallium. Analysis of data no barrier height exhibits an anomalous change in the sense that there is a sharp deterioration in the rectifying nature near this temperature. It is believed to be related changes the phase transition driven physical process e.g. breaking of bonds both between gallium atoms and between gallium atoms and silicon interface; change from long range to short range order in gallium. Strain relaxations at the interface etc.

  1. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

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

    2016-01-01

    . During recent decades, the latter has received increased attention as a route for intentionally delivering drugs to patients. This has stimulated research in methods for sampling, measuring and predicting percutaneous penetration. Previous chapters have described how different endogenous, genetic...... and exogenous factors may affect barrier characteristics. The present chapter introduces the theory for barrier penetration (Fick's law), and describes and discusses different methods for measuring the kinetics of percutaneous penetration of chemicals, including in vitro methods (static and flow......-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...

  2. Security barriers with automated reconnaissance

    Science.gov (United States)

    McLaughlin, James O; Baird, Adam D; Tullis, Barclay J; Nolte, Roger Allen

    2015-04-07

    An intrusion delaying barrier includes primary and secondary physical structures and can be instrumented with multiple sensors incorporated into an electronic monitoring and alarm system. Such an instrumented intrusion delaying barrier may be used as a perimeter intrusion defense and assessment system (PIDAS). Problems with not providing effective delay to breaches by intentional intruders and/or terrorists who would otherwise evade detection are solved by attaching the secondary structures to the primary structure, and attaching at least some of the sensors to the secondary structures. By having multiple sensors of various types physically interconnected serves to enable sensors on different parts of the overall structure to respond to common disturbances and thereby provide effective corroboration that a disturbance is not merely a nuisance or false alarm. Use of a machine learning network such as a neural network exploits such corroboration.

  3. One Unequal Error Control Method for Telemetric Data Transmission

    Science.gov (United States)

    Hirner, Tomáš; Farkaš, Peter; Krile, Srečko

    2011-05-01

    In wireless sensor networks (WSN) it is necessary to use very simple codes for transmission of information since the nodes in these networks have usually only limited energy available not only for transmission but also for processing. On the other hand, common codes do not usually take into account the fact that in case of telemetric information the weights of individual orders are not equal and errors in different orders cause different deviations from correct value. In this contribution, new very simple codes for transmission of telemetric information on WSN will be presented, which take into account the above-mentioned requirements. Resulting square deviation will be used as a quality evaluation criterion.

  4. Perceptions regarding strategic and structural entry barriers

    NARCIS (Netherlands)

    Lutz, Clemens H. M.; Kemp, Ron G. M.; Dijkstra, S. Gerhard

    2010-01-01

    This article uses factor analysis to identify the underlying dimensions of strategic and structural entry barriers. We find that, in the perception of firms, both types of barriers are important and that the effectiveness of strategic barriers depends on attributes of the market structure. Based on

  5. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  6. Barriers to Mammography among Inadequately Screened Women

    Science.gov (United States)

    Stoll, Carolyn R. T.; Roberts, Summer; Cheng, Meng-Ru; Crayton, Eloise V.; Jackson, Sherrill; Politi, Mary C.

    2015-01-01

    Mammography use has increased over the past 20 years, yet more than 30% of women remain inadequately screened. Structural barriers can deter individuals from screening, however, cognitive, emotional, and communication barriers may also prevent mammography use. This study sought to identify the impact of number and type of barriers on mammography…

  7. Storm Surge Barrier: Overview and Design Considerations

    NARCIS (Netherlands)

    Mooyaart, L.F.; Jonkman, S.N.; De Vries, P.A.L.; Van der Toorn, A.; Van Ledden, M.

    2014-01-01

    In this study an overview of existing and planned storm surge barriers in the world is provided. A systematic analysis relates functional requirements (e.g. navigation and tidal exchange) to the main barrier characteristics (e.g. gate type, dimensions). Furthermore, as the costs of barriers are an i

  8. Market barriers to welfare product innovations

    NARCIS (Netherlands)

    Binnekamp, M.H.A.; Ingenbleek, P.T.M.

    2006-01-01

    New products that are based on higher animal welfare standards encounter several barriers on the road to market acceptance. The authors focus on the Dutch poultry sector and distinguish between retailer and consumer barriers. Retailer barriers include the powerful position of retailers, the price co

  9. Removing Barriers to Interdisciplinary Research

    CERN Document Server

    Jacobs, Naomi

    2010-01-01

    A significant amount of high-impact contemporary scientific research occurs where biology, computer science, engineering and chemistry converge. Although programmes have been put in place to support such work, the complex dynamics of interdisciplinarity are still poorly understood. In this paper we interrogate the nature of interdisciplinary research and how we might measure its "success", identify potential barriers to its implementation, and suggest possible mechanisms for removing these impediments.

  10. Overcome barriers to career success

    Energy Technology Data Exchange (ETDEWEB)

    Raudsepp, E.

    1983-04-01

    A test is given to determine if an engineer suffers from one of the three barriers to technical success: fear of success, fear of failure, or perfectionism. As in most such tests, the middle way is best. Successful engineers know that perfection cannot be attained, that they don't have time to worry about failure or success, and that by aiming and perservering in doing things well, success can be achieved.

  11. Filamentary and diffuse barrier discharges

    International Nuclear Information System (INIS)

    Barrier discharges, sometimes also referred to as dielectric-barrier discharges or silent discharges, are characterized by the presence of at least one insulating layer in contact with the discharge between two planar or cylindrical electrodes connected to an ac power supply. The main advantage of this type of electrical discharge is, that non-equilibrium plasma conditions in atmospheric-pressure gases can be established in an economic and reliable way. This has led to a number of important applications including industrial ozone generation, surface modification of polymers, plasma chemical vapor deposition, excitation of CO2 lasers, excimer lamps and, most recently, large-area flat plasma display panels. Depending on the application, the width of the discharge gap can range from less than 0.1 mm to about 100 mm and the applied frequency from below line frequency to several gigahertz. Typical materials used for the insulating layer (dielectric barrier) are glass, quartz, ceramics but also thin enamel or polymer layers

  12. Contributions of the Prion Protein Sequence, Strain, and Environment to the Species Barrier.

    Science.gov (United States)

    Sharma, Aditi; Bruce, Kathryn L; Chen, Buxin; Gyoneva, Stefka; Behrens, Sven H; Bommarius, Andreas S; Chernoff, Yury O

    2016-01-15

    Amyloid propagation requires high levels of sequence specificity so that only molecules with very high sequence identity can form cross-β-sheet structures of sufficient stringency for incorporation into the amyloid fibril. This sequence specificity presents a barrier to the transmission of prions between two species with divergent sequences, termed a species barrier. Here we study the relative effects of protein sequence, seed conformation, and environment on the species barrier strength and specificity for the yeast prion protein Sup35p from three closely related species of the Saccharomyces sensu stricto group; namely, Saccharomyces cerevisiae, Saccharomyces bayanus, and Saccharomyces paradoxus. Through in vivo plasmid shuffle experiments, we show that the major characteristics of the transmission barrier and conformational fidelity are determined by the protein sequence rather than by the cellular environment. In vitro data confirm that the kinetics and structural preferences of aggregation of the S. paradoxus and S. bayanus proteins are influenced by anions in accordance with their positions in the Hofmeister series, as observed previously for S. cerevisiae. However, the specificity of the species barrier is primarily affected by the sequence and the type of anion present during the formation of the initial seed, whereas anions present during the seeded aggregation process typically influence kinetics rather than the specificity of prion conversion. Therefore, our work shows that the protein sequence and the conformation variant (strain) of the prion seed are the primary determinants of cross-species prion specificity both in vivo and in vitro.

  13. Contributions of the Prion Protein Sequence, Strain, and Environment to the Species Barrier.

    Science.gov (United States)

    Sharma, Aditi; Bruce, Kathryn L; Chen, Buxin; Gyoneva, Stefka; Behrens, Sven H; Bommarius, Andreas S; Chernoff, Yury O

    2016-01-15

    Amyloid propagation requires high levels of sequence specificity so that only molecules with very high sequence identity can form cross-β-sheet structures of sufficient stringency for incorporation into the amyloid fibril. This sequence specificity presents a barrier to the transmission of prions between two species with divergent sequences, termed a species barrier. Here we study the relative effects of protein sequence, seed conformation, and environment on the species barrier strength and specificity for the yeast prion protein Sup35p from three closely related species of the Saccharomyces sensu stricto group; namely, Saccharomyces cerevisiae, Saccharomyces bayanus, and Saccharomyces paradoxus. Through in vivo plasmid shuffle experiments, we show that the major characteristics of the transmission barrier and conformational fidelity are determined by the protein sequence rather than by the cellular environment. In vitro data confirm that the kinetics and structural preferences of aggregation of the S. paradoxus and S. bayanus proteins are influenced by anions in accordance with their positions in the Hofmeister series, as observed previously for S. cerevisiae. However, the specificity of the species barrier is primarily affected by the sequence and the type of anion present during the formation of the initial seed, whereas anions present during the seeded aggregation process typically influence kinetics rather than the specificity of prion conversion. Therefore, our work shows that the protein sequence and the conformation variant (strain) of the prion seed are the primary determinants of cross-species prion specificity both in vivo and in vitro. PMID:26565023

  14. Analysing black phosphorus transistors using an analytic Schottky barrier MOSFET model.

    Science.gov (United States)

    Penumatcha, Ashish V; Salazar, Ramon B; Appenzeller, Joerg

    2015-01-01

    Owing to the difficulties associated with substitutional doping of low-dimensional nanomaterials, most field-effect transistors built from carbon nanotubes, two-dimensional crystals and other low-dimensional channels are Schottky barrier MOSFETs (metal-oxide-semiconductor field-effect transistors). The transmission through a Schottky barrier-MOSFET is dominated by the gate-dependent transmission through the Schottky barriers at the metal-to-channel interfaces. This makes the use of conventional transistor models highly inappropriate and has lead researchers in the past frequently to extract incorrect intrinsic properties, for example, mobility, for many novel nanomaterials. Here we propose a simple modelling approach to quantitatively describe the transfer characteristics of Schottky barrier-MOSFETs from ultra-thin body materials accurately in the device off-state. In particular, after validating the model through the analysis of a set of ultra-thin silicon field-effect transistor data, we have successfully applied our approach to extract Schottky barrier heights for electrons and holes in black phosphorus devices for a large range of body thicknesses. PMID:26563458

  15. Review Article: Influenza Transmission on Aircraft

    Science.gov (United States)

    Adlhoch, Cornelia

    2016-01-01

    Background: Air travel is associated with the spread of influenza through infected passengers and potentially through in-flight transmission. Contact tracing after exposure to influenza is not performed systematically. We performed a systematic literature review to evaluate the evidence for influenza transmission aboard aircraft. Methods: Using PubMed and EMBASE databases, we identified and critically appraised identified records to assess the evidence of such transmission to passengers seated in close proximity to the index cases. We also developed a bias assessment tool to evaluate the quality of evidence provided in the retrieved studies. Results: We identified 14 peer-reviewed publications describing contact tracing of passengers after possible exposure to influenza virus aboard an aircraft. Contact tracing during the initial phase of the influenza A(H1N1)pdm09 pandemic was described in 11 publications. The studies describe the follow-up of 2,165 (51%) of 4,252 traceable passengers. Altogether, 163 secondary cases were identified resulting in an overall secondary attack rate among traced passengers of 7.5%. Of these secondary cases, 68 (42%) were seated within two rows of the index case. Conclusion: We found an overall moderate quality of evidence for transmission of influenza virus aboard an aircraft. The major limiting factor was the comparability of the studies. A majority of secondary cases was identified at a greater distance than two rows from the index case. A standardized approach for initiating, conducting, and reporting contact tracing could help to increase the evidence base for better assessing influenza transmission aboard aircraft. PMID:27253070

  16. Infectious disease in animal metapopulations: the importance of environmental transmission.

    Science.gov (United States)

    Park, Andrew W

    2012-07-01

    Motivated by an array of infectious diseases that threaten wildlife populations, a simple metapopulation model (subpopulations connected by animal movement) is developed, which allows for both movement-based and environmental transmission. The model demonstrates that for a range of plausible parameterizations of environmental transmission, increased movement rate of animals between discrete habitats can lead to a decrease in the overall proportion of sites that are occupied. This can limit the ability of the rescue effect to ensure locally extinct populations become recolonized and can drive metapopulations down in size so that extinction by mechanisms other than disease may become more likely. It further highlights that, in the context of environmental transmission, the environmental persistence time of pathogens and the probability of acquiring infection by environmental transmission can affect host metapopulations both qualitatively and quantitatively. Additional spillover sources of infection from alternate reservoir hosts are also included in the model and a synthesis of all three types of transmission, acting alone or in combination, is performed revealing that movement-based transmission is the only necessary condition for a decline in the proportion of occupied sites with increasing movement rate, but that the presence of other types of transmission can reverse this qualitative result. By including the previously neglected role of environmental transmission, this work contributes to the general discussion of when dispersal by wild animals is beneficial or detrimental to populations experiencing infectious disease. PMID:22957148

  17. Physiological barriers to the oral delivery of curcumin

    OpenAIRE

    Škalko-Basnet, Nataša; Berginc, Katja; Trontelj, Jurij; Kristl, Albin

    2015-01-01

    Curcumin, a principal component from Curcuma longa, with antioxidant and anti-inflammatory activities was proposed as a potential candidate for the preventation and/or treatment of cancer and chronic diseases. However, curcumin could not achieve its expected therapeutic outcome in clinical trialsdue to its low solubility and poor bioavailability. The actual intestinal physiological barriers limiting curcumin absorption after oral administration have not been fully investigated. To identify th...

  18. Towards mitigation of greenhouse gases by small changes in farming practices: understanding local barriers in Spain (Article in press)

    OpenAIRE

    Sánchez, Berta; Álvaro Fuentes, Jorge; Ann Cunningham, Ruth; Iglesias Picazo, Ana

    2014-01-01

    Small changes in agricultural practices have a large potential for reducing greenhouse gas emissions. However, the implementation of such practices at the local level is often limited by a range of barriers. Understanding the barriers is essential for defining effective measures, the actual mitigation potential of the measures, and the policy needs to ensure implementation. Here we evaluate behavioural, cultural, and policy barriers for implementation of mitigation practices at the local leve...

  19. A study on the quantitative evaluation of skin barrier function

    Science.gov (United States)

    Maruyama, Tomomi; Kabetani, Yasuhiro; Kido, Michiko; Yamada, Kenji; Oikaze, Hirotoshi; Takechi, Yohei; Furuta, Tomotaka; Ishii, Shoichi; Katayama, Haruna; Jeong, Hieyong; Ohno, Yuko

    2015-03-01

    We propose a quantitative evaluation method of skin barrier function using Optical Coherence Microscopy system (OCM system) with coherency of near-infrared light. There are a lot of skin problems such as itching, irritation and so on. It has been recognized skin problems are caused by impairment of skin barrier function, which prevents damage from various external stimuli and loss of water. To evaluate skin barrier function, it is a common strategy that they observe skin surface and ask patients about their skin condition. The methods are subjective judgements and they are influenced by difference of experience of persons. Furthermore, microscopy has been used to observe inner structure of the skin in detail, and in vitro measurements like microscopy requires tissue sampling. On the other hand, it is necessary to assess objectively skin barrier function by quantitative evaluation method. In addition, non-invasive and nondestructive measuring method and examination changes over time are needed. Therefore, in vivo measurements are crucial for evaluating skin barrier function. In this study, we evaluate changes of stratum corneum structure which is important for evaluating skin barrier function by comparing water-penetrated skin with normal skin using a system with coherency of near-infrared light. Proposed method can obtain in vivo 3D images of inner structure of body tissue, which is non-invasive and non-destructive measuring method. We formulate changes of skin ultrastructure after water penetration. Finally, we evaluate the limit of performance of the OCM system in this work in order to discuss how to improve the OCM system.

  20. The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid.

    Science.gov (United States)

    Olsson, Erik; Menzel, Carolin; Johansson, Caisa; Andersson, Roger; Koch, Kristine; Järnström, Lars

    2013-11-01

    Citric acid cross-linking of starch for e.g. food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barrier coatings. We managed to improve a starch formulation containing citric acid as cross-linking agent for industrial paper coating applications by adjusting the pH of the starch solution. The described starch formulations exhibited both cross-linking of starch by citric acid as well as satisfactory barrier properties, e.g. fairly low OTR values at 50% RH that are comparable with EVOH. Furthermore, it has been shown that barrier properties of coated papers with different solution pH were correlated to molecular changes in starch showing both hydrolysis and cross-linking of starch molecules in the presence of citric acid. Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C. Coated papers showed a minimum in water vapor transmission rate at pH 4 of the starch coating solution, corresponding to the point where hydrolysis was effectively hindered but where a significant degree of cross-linking still occurred.