WorldWideScience

Sample records for atmospheric interference

  1. Modeling and simulation of atmosphere interference signal based on FTIR spectroscopy technique

    Science.gov (United States)

    Zhang, Yugui; Li, Qiang; Yu, Zhengyang; Liu, Zhengmin

    2016-09-01

    Fourier Transform Infrared spectroscopy technique, featured with large frequency range and high spectral resolution, is becoming the research focus in spectrum analysis area, and is spreading in atmosphere detection applications in the aerospace field. In this paper, based on FTIR spectroscopy technique, the principle of atmosphere interference signal generation is deduced in theory, and also its mathematical model and simulation are carried out. Finally, the intrinsic characteristics of the interference signal in time domain and frequency domain, which give a theoretical foundation to the performance parameter design of electrical signal processing, are analyzed.

  2. Autofluorescence of atmospheric bioaerosols – fluorescent biomolecules and potential interferences

    Directory of Open Access Journals (Sweden)

    C. Pöhlker

    2011-09-01

    Full Text Available Primary biological aerosol particles (PBAP are an important subset of air particulate matter with a substantial contribution to the organic aerosol fraction and potentially strong effects on public health and climate. Recent progress has been made in PBAP quantification by utilizing real-time bioaerosol detectors based on the principle that specific organic molecules of biological origin such as proteins, coenzymes, cell wall compounds and pigments exhibit intrinsic fluorescence. The properties of many fluorophores have been well documented, but it is unclear which are most relevant for detection of atmospheric PBAP. The present study provides a systematic synthesis of literature data on potentially relevant biological fluorophores. We analyze and discuss their relative importance for the detection of fluorescent biological aerosol particles (FBAP by online instrumentation for atmospheric measurements such as the ultraviolet aerodynamic particle sizer (UV-APS or the wide issue bioaerosol sensor (WIBS.

    In addition, we provide new laboratory measurement data for selected compounds using bench-top fluorescence spectroscopy. Relevant biological materials were chosen for comparison with existing literature data and to fill in gaps of understanding. The excitation-emission matrices (EEM exhibit pronounced peaks at excitation wavelengths of ~280 nm and ~360 nm, confirming the suitability of light sources used for online detection of FBAP. They also show, however, that valuable information is missed by instruments that do not record full emission spectra at multiple wavelengths of excitation, and co-occurrence of multiple fluorophores within a detected sample will likely confound detailed molecular analysis. Selected non-biological materials were also analyzed to assess their possible influence on FBAP detection and generally exhibit only low levels of background-corrected fluorescent emission. This study strengthens the hypothesis that ambient

  3. Autofluorescence of atmospheric bioaerosols - fluorescent biomolecules and potential interferences

    Science.gov (United States)

    Pöhlker, C.; Huffman, J. A.; Pöschl, U.

    2012-01-01

    Primary biological aerosol particles (PBAP) are an important subset of air particulate matter with a substantial contribution to the organic aerosol fraction and potentially strong effects on public health and climate. Recent progress has been made in PBAP quantification by utilizing real-time bioaerosol detectors based on the principle that specific organic molecules of biological origin such as proteins, coenzymes, cell wall compounds and pigments exhibit intrinsic fluorescence. The properties of many fluorophores have been well documented, but it is unclear which are most relevant for detection of atmospheric PBAP. The present study provides a systematic synthesis of literature data on potentially relevant biological fluorophores. We analyze and discuss their relative importance for the detection of fluorescent biological aerosol particles (FBAP) by online instrumentation for atmospheric measurements such as the ultraviolet aerodynamic particle sizer (UV-APS) or the wide issue bioaerosol sensor (WIBS). In addition, we provide new laboratory measurement data for selected compounds using bench-top fluorescence spectroscopy. Relevant biological materials were chosen for comparison with existing literature data and to fill in gaps of understanding. The excitation-emission matrices (EEM) exhibit pronounced peaks at excitation wavelengths of ~280 nm and ~360 nm, confirming the suitability of light sources used for online detection of FBAP. They also show, however, that valuable information is missed by instruments that do not record full emission spectra at multiple wavelengths of excitation, and co-occurrence of multiple fluorophores within a detected sample will likely confound detailed molecular analysis. Selected non-biological materials were also analyzed to assess their possible influence on FBAP detection and generally exhibit only low levels of background-corrected fluorescent emission. This study strengthens the hypothesis that ambient supermicron particle

  4. Autofluorescence of atmospheric bioaerosols – fluorescent biomolecules and potential interferences

    Directory of Open Access Journals (Sweden)

    C. Pöhlker

    2012-01-01

    Full Text Available Primary biological aerosol particles (PBAP are an important subset of air particulate matter with a substantial contribution to the organic aerosol fraction and potentially strong effects on public health and climate. Recent progress has been made in PBAP quantification by utilizing real-time bioaerosol detectors based on the principle that specific organic molecules of biological origin such as proteins, coenzymes, cell wall compounds and pigments exhibit intrinsic fluorescence. The properties of many fluorophores have been well documented, but it is unclear which are most relevant for detection of atmospheric PBAP. The present study provides a systematic synthesis of literature data on potentially relevant biological fluorophores. We analyze and discuss their relative importance for the detection of fluorescent biological aerosol particles (FBAP by online instrumentation for atmospheric measurements such as the ultraviolet aerodynamic particle sizer (UV-APS or the wide issue bioaerosol sensor (WIBS.

    In addition, we provide new laboratory measurement data for selected compounds using bench-top fluorescence spectroscopy. Relevant biological materials were chosen for comparison with existing literature data and to fill in gaps of understanding. The excitation-emission matrices (EEM exhibit pronounced peaks at excitation wavelengths of ~280 nm and ~360 nm, confirming the suitability of light sources used for online detection of FBAP. They also show, however, that valuable information is missed by instruments that do not record full emission spectra at multiple wavelengths of excitation, and co-occurrence of multiple fluorophores within a detected sample will likely confound detailed molecular analysis. Selected non-biological materials were also analyzed to assess their possible influence on FBAP detection and generally exhibit only low levels of background-corrected fluorescent emission. This study strengthens the hypothesis that ambient

  5. Technical Note: Interference errors in infrared remote sounding of the atmosphere

    Directory of Open Access Journals (Sweden)

    R. Sussmann

    2007-07-01

    Full Text Available Classical error analysis in remote sounding distinguishes between four classes: "smoothing errors," "model parameter errors," "forward model errors," and "retrieval noise errors". For infrared sounding "interference errors", which, in general, cannot be described by these four terms, can be significant. Interference errors originate from spectral residuals due to "interfering species" whose spectral features overlap with the signatures of the target species. A general method for quantification of interference errors is presented, which covers all possible algorithmic implementations, i.e., fine-grid retrievals of the interfering species or coarse-grid retrievals, and cases where the interfering species are not retrieved. In classical retrieval setups interference errors can exceed smoothing errors and can vary by orders of magnitude due to state dependency. An optimum strategy is suggested which practically eliminates interference errors by systematically minimizing the regularization strength applied to joint profile retrieval of the interfering species. This leads to an interfering-species selective deweighting of the retrieval. Details of microwindow selection are no longer critical for this optimum retrieval and widened microwindows even lead to reduced overall (smoothing and interference errors. Since computational power will increase, more and more operational algorithms will be able to utilize this optimum strategy in the future. The findings of this paper can be applied to soundings of all infrared-active atmospheric species, which include more than two dozen different gases relevant to climate and ozone. This holds for all kinds of infrared remote sounding systems, i.e., retrievals from ground-based, balloon-borne, airborne, or satellite spectroradiometers.

  6. Effect of atmospheric interference and sensor noise in retrieval of optically active materials in the ocean by hyperspectral remote sensing.

    Science.gov (United States)

    Levin, Iosif M; Levina, Elizaveta

    2007-10-01

    We present a method to construct the best linear estimate of optically active material concentration from ocean radiance spectra measured through an arbitrary atmosphere layer by a hyperspectral sensor. The algorithm accounts for sensor noise. Optical models of seawater and maritime atmosphere were used to obtain the joint distribution of spectra and concentrations required for the algorithm. The accuracy of phytoplankton retrieval is shown to be substantially lower than that of sediment and dissolved matter. In all cases, the sensor noise noticeably reduces the retrieval accuracy. Additional errors due to atmospheric interference are analyzed, and possible ways to increase the accuracy of retrieval are suggested, such as changing sensor parameters and including a priori information about observation conditions.

  7. Investigation of potential interferences in the detection of atmospheric ROx radicals by laser-induced fluorescence under dark conditions

    Science.gov (United States)

    Fuchs, Hendrik; Tan, Zhaofeng; Hofzumahaus, Andreas; Broch, Sebastian; Dorn, Hans-Peter; Holland, Frank; Künstler, Christopher; Gomm, Sebastian; Rohrer, Franz; Schrade, Stephanie; Tillmann, Ralf; Wahner, Andreas

    2016-04-01

    Direct detection of highly reactive, atmospheric hydroxyl radicals (OH) is widely accomplished by laser-induced fluorescence (LIF) instruments. The technique is also suitable for the indirect measurement of HO2 and RO2 peroxy radicals by chemical conversion to OH. It requires sampling of ambient air into a low-pressure cell, where OH fluorescence is detected after excitation by 308 nm laser radiation. Although the residence time of air inside the fluorescence cell is typically only on the order of milliseconds, there is potential that additional OH is internally produced, which would artificially increase the measured OH concentration. Here, we present experimental studies investigating potential interferences in the detection of OH and peroxy radicals for the LIF instruments of Forschungszentrum Jülich for nighttime conditions. For laboratory experiments, the inlet of the instrument was over flowed by excess synthetic air containing one or more reactants. In order to distinguish between OH produced by reactions upstream of the inlet and artificial signals produced inside the instrument, a chemical titration for OH was applied. Additional experiments were performed in the simulation chamber SAPHIR where simultaneous measurements by an open-path differential optical absorption spectrometer (DOAS) served as reference for OH to quantify potential artifacts in the LIF instrument. Experiments included the investigation of potential interferences related to the nitrate radical (NO3, N2O5), related to the ozonolysis of alkenes (ethene, propene, 1-butene, 2,3-dimethyl-2-butene, α-pinene, limonene, isoprene), and the laser photolysis of acetone. Experiments studying the laser photolysis of acetone yield OH signals in the fluorescence cell, which are equivalent to 0.05 × 106 cm-3 OH for a mixing ratio of 5 ppbv acetone. Under most atmospheric conditions, this interference is negligible. No significant interferences were found for atmospheric concentrations of reactants

  8. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  9. On the interference of 86Kr2+ during carbon isotope analysis of atmospheric methane using continuous flow combustion – isotope ratio mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2013-02-01

    Full Text Available Stable carbon isotope analysis of methane (δ13C of CH4 on atmospheric samples is one key method to constrain the current and past atmospheric CH4 budget. A frequently applied measurement technique is gas chromatography isotope ratio mass spectrometry coupled to a combustion-preconcentration unit. This report shows that the atmospheric trace gas krypton can severely interfere during the mass spectrometric measurement leading to significant biases in δ13C of CH4 if krypton is not sufficiently separated during the analysis. The effect comes about by the lateral tailing of the peak of doubly charged 86Kr in the neighbouring m/z, 44, 45, and 46 Faraday cups. Accordingly, the introduced bias is dependent on the chromatographic separation, the Kr to CH4 mixing ratio in the sample, the mass spectrometer source tuning as well as the detector configuration and can amount to up to several permil in δ13C. Apart from technical solutions to avoid this interference we present correction routines to a posteriori remove the bias.

  10. High concentrations of N2O5 and NO3 observed in daytime with a TD-CIMS: chemical interference or a real atmospheric phenomenon?

    Directory of Open Access Journals (Sweden)

    X. Wang

    2013-08-01

    Full Text Available Dinitrogen pentoxide (N2O5 and the nitrate radical (NO3 play important roles in atmospheric chemistry, yet accurate measurements of their concentrations remain challenging. A thermal dissociation chemical ionization mass spectrometer (TD-CIMS was deployed to an urban site in Hong Kong to measure the sum of N2O5 and NO3 in autumn 2010. To our surprise, very high concentrations of N2O5 + NO3 were frequently observed in daytime, with mixing ratios in the range of 200–1000 pptv. To investigate this unusual phenomenon, various interference tests and measurements with different instrument configuration were conducted. It was found that peroxy acetyl nitrate (PAN contributed to measurable signals at 62 amu, and more importantly, this interference increased significantly with co-existence of NO2. Nitric acid (HNO3, on the other hand, had little interference to the detection of N2O5/NO3 via the NO3− ion in our TD-CIMS. According to the test results, the interference from PAN and NO2 could have contributed to 30–50% of the average daytime (12:00–16:00 LT N2O5 + NO3 signal at our site. However, evidence exists for the presence of elevated daytime N2O5, in addition to the daytime signal at 62 amu. This includes: (1 daytime N2O5 measured via the I(N2O5− cluster ion with an unheated inlet, which subjects to minimum interferences, and (2 observation of elevated daytime ClNO2 (a product of N2O5 hydrolysis during a follow-up study. In view of the difficulty in accurately quantifying the contribution from the interferences of PAN and NO2 and un-tested potential interfering chemicals in the real atmosphere, we caution the use of 62 amu in the TD-CIMS for measuring ambient N2O5 in a high NOx environment like Hong Kong. Additional studies are needed to re-examine the daytime issue using other measurement techniques.

  11. RNA Interference

    Science.gov (United States)

    ... NIGMS Home > Science Education > RNA Interference Fact Sheet RNA Interference Fact Sheet Tagline (Optional) Middle/Main Content Area What is RNA interference? RNA interference (RNAi) is a natural process ...

  12. A comparison of the effectiveness of 6S and SMAC in correcting for atmospheric interference of meteosat second generation images

    DEFF Research Database (Denmark)

    Proud, Simon Richard; Fensholt, R.; Rasmussen, M.O.;

    2010-01-01

    Atmospheric perturbations are a large source of uncertainty in remotely sensed imagery of the Earth's surface. This paper explores the effectiveness of the simplified method for atmospheric correction (SMAC) in reducing the effects of these perturbations in images of the African Continent gathered......-to-high solar or viewing zenith angles (greater than 40°) or in areas with a high ozone or water vapor content (greater than 0.2 cm/atm and 1.5 gm/cm for ozone and water vapor respectively) returning a particularly high relative error. Nevertheless, as the SMAC is up to 3000 times faster in processing a SEVIRI...

  13. Atmospheric temperature profiling in the presence of clouds with a pure rotational Raman lidar by use of an interference-filter-based polychromator.

    Science.gov (United States)

    Behrendt, A; Reichardt, J

    2000-03-20

    A lidar polychromator design for the measurement of atmospheric temperature profiles in the presence of clouds with the rotational Raman method is presented. The design utilizes multicavity interference filters mounted sequentially at small angles of incidence. Characteristics of this design are high signal efficiency and adjustable center wavelengths of the filters combined with a stable and relatively simple experimental setup. High suppression of the elastic backscatter signal in the rotational Raman detection channels allows temperature measurements independent of the presence of thin clouds or aerosol layers; no influence of particle scattering on the lidar temperature profile was observed in clouds with a backscatter ratio of at least 45. The minimum integration time needed for temperature profiling with a statistical temperature error of +/-1 K at, e.g., 20-km height and 960-m height resolution is 1.5 h.

  14. 大气湍流畸变对空间目标清晰干涉成像仿真研究%Simulation for space target interference imaging system distorted by atmospheric turbulence

    Institute of Scientific and Technical Information of China (English)

    刘扬阳; 吕群波; 张文喜

    2012-01-01

    Interference imaging system for space target has close relation with atmospheric environment, and atmospheric turbulence disturbance distorts terribly the wavefront phase of any transmission optics launched from any optics system. In the space target interference imaging system the phase-closure-principle is adopted, in order to eliminate possible effects of atmospheric turbulence on the target image. Based on the power spectrum method and the Fourier transform method, the numerical simulation of wavefront phase screen, which is distorted by atmospheric turbulence conforming to the statistical rules of kolmogonov model and modified Von Karmen model, is respectively implemented. Various images by several different phase-screen models on the interference imaging system are obtained. Simulation results show that, with the advantage of adopting phase-closure-principle, the possible effects of atmospheric turbulence imaging can be eliminated basically.%本文利用功率谱反演法分别展开对符合Kolmogonov统计规律和修正后的VonKarmen统计规律的大气湍流畸变波前相位屏进行了数值模拟研究.得到各种模型下相位屏对该成像系统干涉成像图.仿真结果表明,采用闭合相位原理,基本可以消除大气湍流对光束波前的影响,验证了采用相位闭合技术的优势.

  15. Method to reduce chemical background interference in atmospheric pressure ionization liquid chromatography-mass spectrometry using exclusive reactions with the chemical reagent dimethyl disulfide

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2007-01-01

    The interference of chemical background ions (chemical noise) has been a problem since the inception of mass spectrometry. We present here a novel method to reduce the chemical noise in LC-MS based on exclusive gas-phase reactions with a reactive collision gas in a triple-quadrupole mass spectromete

  16. Toponymic interferences

    Directory of Open Access Journals (Sweden)

    Marius Ilie Oros

    1985-12-01

    Full Text Available The study of linguistic interferences has been greatly extended lately. It comprises all language sections. In onomastics great attention was paid to to the study of macrotoponyms of foreign origin. I would like to mention in this respect the research concerning the toponyms of Slavic origin in Romania and Greece, the toponyms of Romance origin in Yugoslavia etc. The studies referring to the interferences in microtoponymy are more rare. These call for the collecting of all microtoponyms through inquiries made in plaees inhabited by mixed populetion from the ethnic point of view. The microtoponymy of these places off ers a very interesting material as far as the interactiong the reciprocal in.fluences of two or more toponymic systems is concerned.

  17. Method to reduce chemical background interference in atmospheric pressure ionization liquid chromatography-mass spectrometry using exclusive reactions with the chemical reagent dimethyl disulfide.

    Science.gov (United States)

    Guo, Xinghua; Bruins, Andries P; Covey, Thomas R

    2007-06-01

    The interference of chemical background ions (chemical noise) has been a problem since the inception of mass spectrometry. We present here a novel method to reduce the chemical noise in LC-MS based on exclusive gas-phase reactions with a reactive collision gas in a triple-quadrupole mass spectrometer. Combined with the zero neutral loss (ZNL) scan of a triple-quadrupole mass spectrometer, the reactive chemical noise ions can be removed because of shifts of mass-to-charge ratios from the original background ions. The test on various classes of compounds with different functional groups indicates a generic application of this technique in LC-MS. The preliminary results show that a reduction of the level of LC-MS base-peak chromatographic baseline by a factor up to 40 and an improvement of the signal-to-noise ratio by a factor up to 5-10 are achieved on both commercial and custom-modified triple-quadrupole LC-MS systems. Application is foreseen in both quantitative and qualitative trace analysis. It is expected that this chemical noise reduction technique can be optimized on a dedicated mass spectrometric instrumentation which incorporates both a chemical reaction cell for noise reduction and a collision stage for fragmentation.

  18. IETS and quantum interference

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2014-01-01

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low...... suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference....

  19. Opportunistic Interference Alignment in MIMO Interference Channels

    CERN Document Server

    Perlaza, Samir Medina; Lasaulce, Samson; Chaufray, Jean Marie

    2008-01-01

    We present two interference alignment techniques such that an opportunistic point-to-point multiple input multiple output (MIMO) link can reuse, without generating any additional interference, the same frequency band of a similar pre-existing primary link. In this scenario, we exploit the fact that under power constraints, although each radio maximizes independently its rate by water-filling on their channel transfer matrix singular values, frequently, not all of them are used. Therefore, by aligning the interference of the opportunistic radio it is possible to transmit at a significant rate while insuring zero-interference on the pre-existing link. We propose a linear pre-coder for a perfect interference alignment and a power allocation scheme which maximizes the individual data rate of the secondary link. Our numerical results show that significant data rates are achieved even for a reduced number of antennas.

  20. Dark Matter Interference

    DEFF Research Database (Denmark)

    Del Nobile, Eugenio; Kouvaris, Christoforos; Sannino, Francesco

    2012-01-01

    We study different patterns of interference in WIMP-nuclei elastic scattering that can accommodate the DAMA and CoGeNT experiments via an isospin violating ratio $f_n/f_p=-0.71$. We study interference between the following pairs of mediators: Z and Z', Z' and Higgs, and two Higgs fields. We show...

  1. How does interference fall?

    CERN Document Server

    Orlando, Patrick J; Modi, Kavan

    2016-01-01

    We study how single- and double-slit interference patterns fall in the presence of gravity. First, we demonstrate that universality of free fall still holds in this case, i.e., interference patterns fall just like classical objects. Next, we explore lowest order relativistic effects in the Newtonian regime by employing a recent quantum formalism which treats mass as an operator. This leads to interactions between non-degenerate internal degrees of freedom (like spin in an external magnetic field) and external degrees of freedom (like position). Based on these effects, we present an unusual phenomenon, in which a falling double slit interference pattern periodically decoheres and recoheres. The oscillations in the visibility of this interference occur due to correlations built up between spin and position. Finally, we connect the interference visibility revivals with non-Markovian quantum dynamics.

  2. Recovery of dynamic interference

    CERN Document Server

    Baghery, Mehrdad; Rost, Jan M

    2016-01-01

    We develop general quantitative criteria for dynamic interference, a manifestation of double-slit interference in time which should be realizable with brilliant state-of-the-art high-frequency laser sources. Our analysis reveals that the observation of dynamic interference hinges upon maximizing the difference between the dynamic polarization of the initial bound and the final continuum state of the electron during the light pulse, while keeping depletion of the initial state small. Confirmed by numerical results, we predict that this is impossible for the hydrogen ground-state but feasible with excited states explicitly exemplified with the hydrogen 2p-state.

  3. Group Based Interference Alignment

    CERN Document Server

    Ma, Yanjun; Chen, Rui; Yao, Junliang

    2010-01-01

    in $K$-user single-input single-output (SISO) frequency selective fading interference channels, it is shown that the achievable multiplexing gain is almost surely $K/2$ by using interference alignment (IA). However when the signaling dimensions is limited, allocating all the resource to all the users simultaneously is not optimal. According to this problem, a group based interference alignment (GIA) scheme is proposed and a search algorithm is designed to get the group patterns and the resource allocation among them. Analysis results show that our proposed scheme achieves a higher multiplexing gain when the resource is limited.

  4. Understanding ghost interference

    Science.gov (United States)

    Qureshi, Tabish; Chingangbam, Pravabati; Shafaq, Sheeba

    2016-08-01

    The ghost interference observed for entangled photons is theoretically analyzed using wave-packet dynamics. It is shown that ghost interference is a combined effect of virtual double-slit creation due to entanglement, and quantum erasure of which-path information for the interfering photon. For the case where the two photons are of different color, it is shown that fringe width of the interfering photon depends not only on its own wavelength, but also on the wavelength of the other photon which it is entangled with.

  5. Destructive Interference of Dualities

    CERN Document Server

    Wotzasek, C

    1998-01-01

    We show that the fusion of two (diffeomorphism) invariant self-dual scalars described by right and left chiral-WZW actions, produces a Hull non-mover field. After fusion, right and left moving modes disappear from the spectrum, displaying in this way the phenomenon of (destructive) quantum interference of dualities.

  6. Downlink Interference Alignment

    CERN Document Server

    Suh, Changho; Tse, David

    2010-01-01

    We develop an interference alignment (IA) technique for a downlink cellular system. In the uplink, IA schemes need channel-state-information exchange across base-stations of different cells, but our downlink IA technique requires feedback only within a cell. As a result, the proposed scheme can be implemented with a few changes to an existing cellular system where the feedback mechanism (within a cell) is already being considered for supporting multi-user MIMO. Not only is our proposed scheme implementable with little effort, it can in fact provide substantial gain especially when interference from a dominant interferer (base-station) is significantly stronger than the remaining interference: it is shown that in the two-isolated cell layout, our scheme provides four-fold gain in throughput performance over a standard multi-user MIMO technique. We show through simulations that our technique provides respectable gain under more realistic scenarios: it gives approximately 55% and 20% gain for a linear cell layou...

  7. Quantum interference in polyenes

    Science.gov (United States)

    Tsuji, Yuta; Hoffmann, Roald; Movassagh, Ramis; Datta, Supriyo

    2014-12-01

    The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or by an odd number of carbons at both ends (transmission turned on or annihilated). These prescriptions for the occurrence of quantum interference lead to an unexpected consequence for switches which realize such extension through electrocyclic reactions: for some specific attachment modes the chemically closed ring will be the ON position of the switch. Normally the signs of the entries of the Green's function matrix are assumed to have no physical significance; however, we show that the signs may have observable consequences. In particular, in the case of multiple probe attachments - if coherence in probe connections can be arranged - in some cases new destructive interference results, while in others one may have constructive interference. One such case may already exist in the literature.

  8. Quantum interference in polyenes

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Yuta; Hoffmann, Roald, E-mail: rh34@cornell.edu [Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853 (United States); Movassagh, Ramis [Department of Mathematics, Northeastern University, Boston, Massachusetts 02115, USA and Department of Mathematics, Massachusetts Institute of Technology, Building E18, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307 (United States); Datta, Supriyo [School of Electrical and Computer Engineering, Purdue University, Electrical Engineering Building, 465 Northwestern Ave., West Lafayette, Indiana 47907-2035 (United States)

    2014-12-14

    The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or by an odd number of carbons at both ends (transmission turned on or annihilated). These prescriptions for the occurrence of quantum interference lead to an unexpected consequence for switches which realize such extension through electrocyclic reactions: for some specific attachment modes the chemically closed ring will be the ON position of the switch. Normally the signs of the entries of the Green's function matrix are assumed to have no physical significance; however, we show that the signs may have observable consequences. In particular, in the case of multiple probe attachments – if coherence in probe connections can be arranged – in some cases new destructive interference results, while in others one may have constructive interference. One such case may already exist in the literature.

  9. Interference Alignment for Secrecy

    CERN Document Server

    Koyluoglu, Onur Ozan; Lai, Lifeng; Poor, H Vincent

    2008-01-01

    This paper studies the frequency/time selective $K$-user Gaussian interference channel with secrecy constraints. Two distinct models, namely the interference channel with confidential messages and the one with an external eavesdropper, are analyzed. The key difference between the two models is the lack of channel state information (CSI) about the external eavesdropper. Using interference alignment along with secrecy pre-coding, it is shown that each user can achieve non-zero secure Degrees of Freedom (DoF) for both cases. More precisely, the proposed coding scheme achieves $\\frac{K-2}{2K-2}$ secure DoF {\\em with probability one} per user in the confidential messages model. For the external eavesdropper scenario, on the other hand, it is shown that each user can achieve $\\frac{K-2}{2K}$ secure DoF {\\em in the ergodic setting}. Remarkably, these results establish the {\\em positive impact} of interference on the secrecy capacity region of wireless networks.

  10. Interference and radioastronomy

    Science.gov (United States)

    Thompson, A. R.; Vanden Bout, Paul A.; Gergely, Tomas E.

    1991-11-01

    The vulnerabilty of radio astronomy to the growing flood of interfering sources ranging from garage door openers to digital audio broadcast satellites is reviewed. Technical solutions to these problems are briefly examined, and work that needs to be done in the international regulatory system to ameliorate the interference is addressed. An overview is given of existing regulations.

  11. Interference Decoding for Deterministic Channels

    CERN Document Server

    Bandemer, Bernd

    2010-01-01

    An inner bound to the capacity region of a class of three user pair deterministic interference channels is presented. The key idea is to simultaneously decode the combined interference signal and the intended message at each receiver. It is shown that this interference decoding inner bound is strictly larger than the inner bound obtained by treating interference as noise, which includes interference alignment for deterministic channels. The gain comes from judicious analysis of the number of combined interference sequences in different regimes of input distributions and message rates.

  12. Transmission of Correlated Messages over Interference Channels with Strong Interference

    Science.gov (United States)

    Choi, Suhan; Yoon, Eunchul; Moon, Hichan

    Transmission of correlated messages over interference channels with strong interference is considered. As a result, an achievable rate region is presented. It is shown that if the messages are correlated, the achievable rate region can be larger than the capacity region given by Costa and El Gamal. As an example, the Gaussian interference channel is considered.

  13. Holographic interference filters

    Science.gov (United States)

    Diehl, Damon W.

    Holographic mirrors have wavelength-selection properties and thus qualify as a class of interference filters. Two theoretical methods for analyzing such structures are developed. The first method uses Hill's matrix method to yield closed-forms solutions in terms of the Floquet-Bloch waves within a periodic structure. A process is developed for implementing this solution method on a computer, using sparse-matrix memory allocation, numerical root-finding algorithms, and inverse-iteration techniques. It is demonstrated that Hill's matrix method is valid for the analysis of finite and multi-periodic problems. The second method of theoretical analysis is a transfer-matrix technique, which is herein termed thin-film decomposition. It is shown that the two methods of solution yield results that differ by, at worst, a fraction of a percent. Using both calculation techniques, a number of example problems are explored. Of key importance is the construction of a set of curves that are useful for the design and characterization of holographic interference filters. In addition to the theoretical development, methods are presented for the fabrication of holographic interference filters using DuPont HRF-800X001 photopolymer. Central to the exposure system is a frequency-stabilized, tunable dye laser. The types of filters fabricated include single-tone reflection filters, two types of multitone reflection filters, and reflection filters for infrared wavelengths. These filters feature index profiles that are not easily attainable through other fabrication methods. As a supplement to the body of the dissertation, the computer algorithms developed to implement Hill's matrix method and thin-film decomposition are also included as an appendix. Further appendices provide more information on Floquet's theorem and Hill's matrix method. A final appendix presents a design for an infrared laser spectrophotometer.

  14. RNA interference in Lepidoptera

    DEFF Research Database (Denmark)

    Terenius, Ole; Papanicolaou, Alexie; Garbutt, Jennie S.

    2011-01-01

    Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive...... is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success...

  15. Partial Interference Alignment for K-user MIMO Interference Channels

    CERN Document Server

    Huang, Huang

    2011-01-01

    In this paper, we consider a Partial Interference Alignment and Interference Detection (PIAID) design for $K$-user quasi-static MIMO interference channels with discrete constellation inputs. Each transmitter has M antennas and transmits L independent data streams to the desired receiver with N receive antennas. We focus on the case where not all K-1 interfering transmitters can be aligned at every receiver. As a result, there will be residual interference at each receiver that cannot be aligned. Each receiver detects and cancels the residual interference based on the constellation map. However, there is a window of unfavorable interference profile at the receiver for Interference Detection (ID). In this paper, we propose a low complexity Partial Interference Alignment scheme in which we dynamically select the user set for IA so as to create a favorable interference profile for ID at each receiver. We first derive the average symbol error rate (SER) by taking into account of the non-Guassian residual interfere...

  16. Graphene quantum interference photodetector

    Directory of Open Access Journals (Sweden)

    Mahbub Alam

    2015-03-01

    Full Text Available In this work, a graphene quantum interference (QI photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach–Zehnder interferometer (MZI, which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector, low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  17. Sensing via optical interference

    Directory of Open Access Journals (Sweden)

    Ryan C. Bailey

    2005-04-01

    Full Text Available Chemical and biological sensing are problems of tremendous contemporary technological importance in multiple regulatory and human health contexts, including environmental monitoring, water quality assurance, workplace air quality assessment, food quality control, many aspects of biodiagnostics, and, of course, homeland security. Frequently, what is needed, or at least wanted, are sensors that are simultaneously cheap, fast, reliable, selective, sensitive, robust, and easy to use. Unfortunately, these are often conflicting requirements. Over the past few years, however, a number of promising ideas based on optical interference effects have emerged. Each is based to some extent on advances in the design and fabrication of functional materials. Generally, the advances are of two kinds: chemo- and bio-selective recognition and binding, and efficient methods for micropatterning or microstructuring.

  18. Graphene quantum interference photodetector.

    Science.gov (United States)

    Alam, Mahbub; Voss, Paul L

    2015-01-01

    In this work, a graphene quantum interference (QI) photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach-Zehnder interferometer (MZI), which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector), low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  19. Quantum Interference in Graphene Nanoconstrictions.

    Science.gov (United States)

    Gehring, Pascal; Sadeghi, Hatef; Sangtarash, Sara; Lau, Chit Siong; Liu, Junjie; Ardavan, Arzhang; Warner, Jamie H; Lambert, Colin J; Briggs, G Andrew D; Mol, Jan A

    2016-07-13

    We report quantum interference effects in the electrical conductance of chemical vapor deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multimode Fabry-Pérot interferences can be attributed to reflections at potential steps inside the channel. Sharp antiresonance features with a Fano line shape are observed. Theoretical modeling reveals that these Fano resonances are due to localized states inside the constriction, which couple to the delocalized states that also give rise to the Fabry-Pérot interference patterns. This study provides new insight into the interplay between two fundamental forms of quantum interference in graphene nanoconstrictions.

  20. A comparison of peak pressure interference factors interference factors for high-rise buildings determined in two ABL wind tunnels

    NARCIS (Netherlands)

    Bronkhorst, A.J.; Uffelen, M. van; Geurts, C.P.W.; Aanen, L.; Bentum, C.A. van

    2013-01-01

    Pressure measurements were performed on various configurations of two high-rise building models in two atmospheric boundary layer wind tunnels in the Netherlands. A comparison was made of the interference factors of the minimum and maximum peak pressures over all pressure taps at 0 degree angle of i

  1. Interference in ballistic motor learning - is motor interference really sensory?

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards. We hypothesised that interference requires the same circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects...... not require learning. Repeated transcranial magnetic stimulation (rTMS) of corticospinal motor output at intensities below ankle movement threshold did not cause interference, whereas suprathreshold rTMS did. Furthermore, electrical stimulation of the peripheral nerve to the plantarflexors (but not extensors......) caused interference. We conclude that interference is remarkably specific for circuits involved in a specific movement direction / activation of individual muscles and depends crucially on sensory error signals. One possible mechanism of interference may be disruption of early motor memory consolidation....

  2. Numerical Simulation and Characteristics Analysis of Laser Self-Mixing Interference Measurement of Atmospheric Particle Parameters%大气颗粒物多参数激光自混合传感的数值模拟与特性分析

    Institute of Scientific and Technical Information of China (English)

    王秀利; 桂华侨; 陆亦怀; 刘建国; 王杰; 伍德侠

    2012-01-01

    基于颗粒物米氏散射特性、激光自混合三镜腔理论和激光器稳态条件,推导出在大气颗粒物光反馈下激光器频率、功率、线宽的理论表达式,建立了大气颗粒物光反馈下的激光自混合理论模型.同时,数值模拟和分析了大气颗粒物物理参数对激光自混合干涉信号的影响.结果表明,在一定粒径范围内,激光自混合反馈强度随大气颗粒物粒径增大先增大后减小,且反馈强度峰值出现的位置随颗粒物折射率实部的增大、虚部的减小向粒径较大处移动;自混合系统的外腔长度影响自混合干涉信号的波动深度,激光器输出光信号的幅值随外腔长度增大呈指数衰减;自混合干涉信号波动频率与大气颗粒物运动速度呈线性关系.分析结果对基于激光自混合效应的大气颗粒物多物理参数传感具有重要作用.%The theoretical expressions describing the self-mixing interference laser frequency, output power, and linewidth under the weak feedback of atmospheric particles are deduced based on the Mie scattering theory, the three-mirror theory and the steady-state equations of laser. The theory model of self-mixing effect feedback from atmospheric particles is established. And the relationship between the self-mixing signals and the physical parameters of atmospheric particles is analyzed in detail. The result shows that in a certain particle size range, the laser self-mixing signal intensity increases with the particle size and then decreases. With the increase of the real part and decrease of the imaginary part in atmospheric particle complex refractive index, the location of the external feedback strength peak value gradually moves to larger particle size. The amplitude of self-mixing signals is exponential decay with the increase of the external feedback cavity; the fluctuation frequency of the laser intensity is linearly related to the velocity of atmospheric particles. These

  3. Output Interference in Recognition Memory

    Science.gov (United States)

    Criss, Amy H.; Malmberg, Kenneth J.; Shiffrin, Richard M.

    2011-01-01

    Dennis and Humphreys (2001) proposed that interference in recognition memory arises solely from the prior contexts of the test word: Interference does not arise from memory traces of other words (from events prior to the study list or on the study list, and regardless of similarity to the test item). We evaluate this model using output…

  4. Sleep can reduce proactive interference.

    Science.gov (United States)

    Abel, Magdalena; Bäuml, Karl-Heinz T

    2014-01-01

    Sleep has repeatedly been connected to processes of memory consolidation. While extensive research indeed documents beneficial effects of sleep on memory, little is yet known about the role of sleep for interference effects in episodic memory. Although two prior studies reported sleep to reduce retroactive interference, no sleep effect has previously been found for proactive interference. Here we applied a study format differing from that employed by the prior studies to induce a high degree of proactive interference, and asked participants to encode a single list or two interfering lists of paired associates via pure study cycles. Testing occurred after 12 hours of diurnal wakefulness or nocturnal sleep. Consistent with the prior work, we found sleep in comparison to wake did not affect memory for the single list, but reduced retroactive interference. In addition we found sleep reduced proactive interference, and reduced retroactive and proactive interference to the same extent. The finding is consistent with the view that arising benefits of sleep are caused by the reactivation of memory contents during sleep, which has been suggested to strengthen and stabilise memories. Such stabilisation may make memories less susceptible to competition from interfering memories at test and thus reduce interference effects.

  5. The RNA interference revolution

    Directory of Open Access Journals (Sweden)

    G. Lenz

    2005-12-01

    Full Text Available The discovery of double-stranded RNA-mediated gene silencing has rapidly led to its use as a method of choice for blocking a gene, and has turned it into one of the most discussed topics in cell biology. Although still in its infancy, the field of RNA interference has already produced a vast array of results, mainly in Caenorhabditis elegans, but recently also in mammalian systems. Micro-RNAs are short hairpins of RNA capable of blocking translation, which are transcribed from genomic DNA and are implicated in several aspects from development to cell signaling. The present review discusses the main methods used for gene silencing in cell culture and animal models, including the selection of target sequences, delivery methods and strategies for a successful silencing. Expected developments are briefly discussed, ranging from reverse genetics to therapeutics. Thus, the development of the new paradigm of RNA-mediated gene silencing has produced two important advances: knowledge of a basic cellular mechanism present in the majority of eukaryotic cells and access to a potent and specific new method for gene silencing.

  6. Communications in interference limited networks

    CERN Document Server

    2016-01-01

    This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

  7. Interference in motor learning - is motor interference sensory?

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye; Petersen, Tue Hvass; Rothwell, John C

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards, but not all motor activities cause interference. After all it is not necessary to remain completely still after practicing a task for learning to occur. Here we ask which...... mechanisms determine whether or not interference occurs. We hypothesised that interference requires the same neural circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects learned a ballistic ankle plantarflexion task. Early motor memory...... learning of the primary task, no interference was observed. Previous studies have suggested that primary motor cortex (M1) may be involved in early motor memory consolidation. 1Hz Repetitive Transcranial Magnetic Stimulation (rTMS) of corticospinal motor output at intensities below ankle movement threshold...

  8. Optical interference with digital holograms

    Science.gov (United States)

    Gossman, David; Perez-Garcia, Benjamin; Hernandez-Aranda, Raul I.; Forbes, Andrew

    2016-07-01

    In 1804, Thomas Young reported the observation of fringes in the intensity of light, and attributed it to the concept of interference between coherent sources. In this paper, we revisit this famous experiment and show how it can easily be demonstrated with digital holography. We look closely at the concept of interference with light and ask, "fringes in what?" We then show that depending on how light interferes, fringe patterns in observables other than intensity can be seen. We explain this conceptually and demonstrate it experimentally. We provide a holistic approach to the topic, aided by modern laboratory practices for a straightforward demonstration of the underlying physics.

  9. Multipolar interference effects in nanophotonics

    CERN Document Server

    Liu, Wei

    2016-01-01

    Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows to describe the scattering intensity and radiation pattern through interferences of dominating excited multipole modes. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here we review the multipolar interference effects in metallic, metal-dielectric, and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and nonradiating optical anapoles. We further discuss other types of possible ...

  10. Interference of Quantum Market Strategies

    CERN Document Server

    Piotrowski, E W; Syska, J

    2003-01-01

    Recent development in quantum computation and quantum information theory allows to extend the scope of game theory for the quantum world. The paper is devoted to the analysis of interference of quantum strategies in quantum market games.

  11. Interference Phenomena in Quantum Information

    CERN Document Server

    Stefanak, Martin

    2010-01-01

    One of the key features of quantum mechanics is the interference of probability amplitudes. The reason for the appearance of interference is mathematically very simple. It is the linear structure of the Hilbert space which is used for the description of quantum systems. In terms of physics we usually talk about the superposition principle valid for individual and composed quantum objects. So, while the source of interference is understandable it leads in fact to many counter-intuitive physical phenomena which puzzle physicists for almost hundred years. The present thesis studies interference in two seemingly disjoint fields of physics. However, both have strong links to quantum information processing and hence are related. In the first part we study the intriguing properties of quantum walks. In the second part we analyze a sophisticated application of wave packet dynamics in atoms and molecules for factorization of integers. The main body of the thesis is based on the original contributions listed separately...

  12. Interference, reduced action, and trajectories

    OpenAIRE

    2006-01-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichroma...

  13. Multipolar interference effects in nanophotonics.

    Science.gov (United States)

    Liu, Wei; Kivshar, Yuri S

    2017-03-28

    Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows one to describe the scattering intensity and radiation pattern through interferences of dominating multipole modes excited. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here, we review the multipolar interference effects in metallic, metal-dielectric and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and non-radiating optical anapoles. We further discuss other types of possible multipolar interference effects not yet exploited in the literature and envisage the prospect of achieving more flexible and advanced nanoscale control of light relying on the concepts of multipolar interference through full phase and amplitude engineering.This article is part of the themed issue 'New horizons for nanophotonics'.

  14. Demonstrations of Beats as Moving Interference Patterns.

    Science.gov (United States)

    Stein, T. S.; Dishman, L. G.

    1982-01-01

    Describes a ripple tank demonstration that displays interference patterns responsible for producing beats and provides photographs of computer simulations of various beat interference patterns. Includes programs for the computer simulation and equations of constructive interference paths in beat interference patterns. (Author/SK)

  15. Whirling waves in Interference experiments

    Science.gov (United States)

    Sinha, Urbasi; Sawant, Rahul; Samuel, Joseph; Sinha, Aninda; Sinha, Supurna

    2014-03-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well- known text books in quantum mechanics implicitly and/or explicitly use this assumption, the wave function hypothesis, which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in interference experiments which provide a measurable deviation from the wave function hypothesis. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence. I will also describe some ongoing experimental efforts towards testing our theoretical findings.

  16. Transmission Techniques for Relay-Interference Networks

    CERN Document Server

    Mohajer, Soheil; Fragouli, Christina; Tse, David N C

    2008-01-01

    In this paper we study the relay-interference wireless network, in which relay (helper) nodes are to facilitate competing information flows over a wireless network. We examine this in the context of a deterministic wireless interaction model, which eliminates the channel noise and focuses on the signal interactions. Using this model, we show that almost all the known schemes such as interference suppression, interference alignment and interference separation are necessary for relay-interference networks. In addition, we discover a new interference management technique, which we call interference neutralization, which allows for over-the-air interference removal, without the transmitters having complete access the interfering signals. We show that interference separation, suppression, and neutralization arise in a fundamental manner, since we show complete characterizations for special configurations of the relay-interference network.

  17. "Quantum Interference with Slits" Revisited

    CERN Document Server

    Rothman, Tony

    2010-01-01

    Marcella [arXiv:quant-ph/0703126] has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his calculation as if no approximations are employed. We show that he implicitly makes the same approximations found in classical treatments of interference and that no new physics has been introduced. At the same time, some of the quantum mechanical arguments Marcella gives are, at best, misleading.

  18. Interference of diffusive light waves.

    Science.gov (United States)

    Schmitt, J M; Knüttel, A; Knutson, J R

    1992-10-01

    We examine interference effects resulting from the superposition of photon-density waves produced by coherently modulated light incident upon a turbid medium. Photon-diffusion theory is used to derive expressions for the ac magnitude and phase of the aggregate diffusive wave produced in full- and half-space volumes by two sources. Using a frequency-domain spectrometer operating at 410 MHz, we verify interference patterns predicted by the model in scattering samples having optical properties similar to those of skin tissue. Potential imaging applications of interfering diffusive waves are discussed in the context of the theoretical and experimental results.

  19. Interference, Reduced Action, and Trajectories

    Science.gov (United States)

    Floyd, Edward R.

    2007-09-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the trajectories of the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichromatic wave function’s trajectory. The quantum effective mass renders insight into the behavior of the trajectory. The trajectory in turn renders insight into quantum nonlocality.

  20. Interference, reduced action, and trajectories

    CERN Document Server

    Floyd, E R

    2006-01-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichromatic wave function's trajectory. The quantum effective mass renders insight into the behavior of the trajectory. The trajectory in turn renders insight into quantum nonlocality.

  1. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...... localities of tensions between matter and the immaterial, the practical and the ideal, and subject and object. In the colloquial language there can, moreover, often seem to be something authentic or genuine about atmosphere, juxtaposing it to staging, which is implied to be something simulated or artificial....... This introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  2. "Quantum Interference with Slits" Revisited

    Science.gov (United States)

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his…

  3. Political Interference in Climate Science

    Science.gov (United States)

    Kumar, Mohi

    2007-02-01

    ``All of us have a right to our own views about the seriousness of global warming,'' U.S. Rep. Henry Waxman (D-Calif.), chair of the House Oversight and Government Reform Committee, said at a 30 January committee hearing held to examine political interference in climate science. ``But we don't have a right to our own science.''

  4. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  5. Atmospheric Neutrinos

    OpenAIRE

    Takaaki Kajita

    1994-01-01

    Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses...

  6. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design...

  7. Atmospheric Neutrinos

    Directory of Open Access Journals (Sweden)

    Takaaki Kajita

    2012-01-01

    Full Text Available Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses atmospheric neutrino experiments and the neutrino oscillation studies with these neutrinos.

  8. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  9. REM sleep rescues learning from interference.

    Science.gov (United States)

    McDevitt, Elizabeth A; Duggan, Katherine A; Mednick, Sara C

    2015-07-01

    Classical human memory studies investigating the acquisition of temporally-linked events have found that the memories for two events will interfere with each other and cause forgetting (i.e., interference; Wixted, 2004). Importantly, sleep helps consolidate memories and protect them from subsequent interference (Ellenbogen, Hulbert, Stickgold, Dinges, & Thompson-Schill, 2006). We asked whether sleep can also repair memories that have already been damaged by interference. Using a perceptual learning paradigm, we induced interference either before or after a consolidation period. We varied brain states during consolidation by comparing active wake, quiet wake, and naps with either non-rapid eye movement sleep (NREM), or both NREM and REM sleep. When interference occurred after consolidation, sleep and wake both produced learning. However, interference prior to consolidation impaired memory, with retroactive interference showing more disruption than proactive interference. Sleep rescued learning damaged by interference. Critically, only naps that contained REM sleep were able to rescue learning that was highly disrupted by retroactive interference. Furthermore, the magnitude of rescued learning was correlated with the amount of REM sleep. We demonstrate the first evidence of a process by which the brain can rescue and consolidate memories damaged by interference, and that this process requires REM sleep. We explain these results within a theoretical model that considers how interference during encoding interacts with consolidation processes to predict which memories are retained or lost.

  10. Parasitic interference in nulling interferometry

    CERN Document Server

    Matter, Alexis; Danchi, William C; Lopez, Bruno; Absil, Olivier

    2013-01-01

    Nulling interferometry aims to detect faint objects close to bright stars. Its principle is to produce a destructive interference along the line-of-sight so that the stellar flux is rejected, while the flux of the off-axis source can be transmitted. In practice, various instrumental perturbations can degrade the nulling performance. Any imperfection in phase, amplitude, or polarization produces a spurious flux that leaks to the interferometer output and corrupts the transmitted off-axis flux. One of these instrumental pertubations is the crosstalk phenomenon, which occurs because of multiple parasitic reflections inside transmitting optics, and/or diffraction effects related to beam propagation along finite size optics. It can include a crosstalk of a beam with itself, and a mutual crosstalk between different beams. This can create a parasitic interference pattern, which degrades the intrinsic transmission map - or intensity response - of the interferometer. In this context, we describe how this instrumental ...

  11. Silicon superconducting quantum interference device

    Energy Technology Data Exchange (ETDEWEB)

    Duvauchelle, J. E.; Francheteau, A.; Marcenat, C.; Lefloch, F., E-mail: francois.lefloch@cea.fr [Université Grenoble Alpes, CEA - INAC - SPSMS, F-38000 Grenoble (France); Chiodi, F.; Débarre, D. [Université Paris-sud, CNRS - IEF, F-91405 Orsay - France (France); Hasselbach, K. [Université Grenoble Alpes, CNRS - Inst. Néel, F-38000 Grenoble (France); Kirtley, J. R. [Center for probing at nanoscale, Stanford University, Palo Alto, California 94305-4045 (United States)

    2015-08-17

    We have studied a Superconducting Quantum Interference Device (SQUID) made from a single layer thin film of superconducting silicon. The superconducting layer is obtained by heavily doping a silicon wafer with boron atoms using the gas immersion laser doping technique. The SQUID is composed of two nano-bridges (Dayem bridges) in a loop and shows magnetic flux modulation at low temperature and low magnetic field. The overall behavior shows very good agreement with numerical simulations based on the Ginzburg-Landau equations.

  12. Interference Mitigation in Cognitive Femtocells

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira; Cattoni, Andrea Fabio; Alvarez Roig, Victor;

    2010-01-01

    in densely deployed femto scenarios. In this paper, two key elements of cognitive femtocells are combined: a power control algorithm and a fully distributed dynamic spectrum allocation method. The resulting solution was evaluated through system-level simulations and compared to the separate algorithms...... and fixed frequency reuses. The outage throughput performance of the combined algorithm exceeds all other options, proving the efficiency of the method in reducing inter-cell interference....

  13. RNA干扰%RNA Interference

    Institute of Scientific and Technical Information of China (English)

    陈颖; 朱明华

    2003-01-01

    RNA干扰(RNA interference,RNAi)是一种古老的生物抗病毒机制,能介导序列特异性的mRNA降解,是基因功能研究和蛋白组学的有效工具,在药物靶基因的筛选、抗病毒、肿瘤基因治疗等领域有很好的发展前景.

  14. CRISPR interference: a structural perspective

    Science.gov (United States)

    Reeks, Judith; Naismith, James H.; White, Malcolm F.

    2013-01-01

    CRISPR (cluster of regularly interspaced palindromic repeats) is a prokaryotic adaptive defence system, providing immunity against mobile genetic elements such as viruses. Genomically encoded crRNA (CRISPR RNA) is used by Cas (CRISPR-associated) proteins to target and subsequently degrade nucleic acids of invading entities in a sequence-dependent manner. The process is known as ‘interference’. In the present review we cover recent progress on the structural biology of the CRISPR/Cas system, focusing on the Cas proteins and complexes that catalyse crRNA biogenesis and interference. Structural studies have helped in the elucidation of key mechanisms, including the recognition and cleavage of crRNA by the Cas6 and Cas5 proteins, where remarkable diversity at the level of both substrate recognition and catalysis has become apparent. The RNA-binding RAMP (repeat-associated mysterious protein) domain is present in the Cas5, Cas6, Cas7 and Cmr3 protein families and RAMP-like domains are found in Cas2 and Cas10. Structural analysis has also revealed an evolutionary link between the small subunits of the type I and type III-B interference complexes. Future studies of the interference complexes and their constituent components will transform our understanding of the system. PMID:23805973

  15. Improved Linear Parallel Interference Cancellers

    CERN Document Server

    Srikanth, T; Chockalingam, A; Milstein, L B

    2007-01-01

    In this paper, taking the view that a linear parallel interference canceller (LPIC) can be seen as a linear matrix filter, we propose new linear matrix filters that can result in improved bit error performance compared to other LPICs in the literature. The motivation for the proposed filters arises from the possibility of avoiding the generation of certain interference and noise terms in a given stage that would have been present in a conventional LPIC (CLPIC). In the proposed filters, we achieve such avoidance of the generation of interference and noise terms in a given stage by simply making the diagonal elements of a certain matrix in that stage equal to zero. Hence, the proposed filters do not require additional complexity compared to the CLPIC, and they can allow achieving a certain error performance using fewer LPIC stages. We also extend the proposed matrix filter solutions to a multicarrier DS-CDMA system, where we consider two types of receivers. In one receiver (referred to as Type-I receiver), LPIC...

  16. 49 CFR 193.2633 - Interference currents.

    Science.gov (United States)

    2010-10-01

    ...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize...

  17. Distributed Interference Alignment with Low Overhead

    CERN Document Server

    Ma, Yanjun; Chen, Rui

    2011-01-01

    Based on closed-form interference alignment (IA) solutions, a low overhead distributed interference alignment (LOIA) scheme is proposed in this paper for the $K$-user SISO interference channel, and extension to multiple antenna scenario is also considered. Compared with the iterative interference alignment (IIA) algorithm proposed by Gomadam et al., the overhead is greatly reduced. Simulation results show that the IIA algorithm is strictly suboptimal compared with our LOIA algorithm in the overhead-limited scenario.

  18. Canceling Stationary Interference Signals Exploiting Secondary Data

    OpenAIRE

    Swärd, Johan; Jakobsson, Andreas

    2014-01-01

    In this paper, we propose a novel interference cancellation method that exploits secondary data to estimate stationary interference components present in both the primary and the secondary data sets, thereby allowing for the removal of such interference from the data sets, even when these components share frequencies with the signal of interest. The algorithm estimates the present interference components one frequency at a time, thus enabling for a computationally efficient algorithm, that re...

  19. An accumulator model of semantic interference

    NARCIS (Netherlands)

    van Maanen, Leendert; van Rijn, Hedderik

    2007-01-01

    To explain latency effects in picture-word interference tasks, cognitive models need to account for both interference and stimulus onset asynchrony (SOA) effects. As opposed to most models of picture-word interference, which model the time course during the task in a ballistic manner, the RACE model

  20. Atmospheric materiality

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2016-01-01

    experience and, consequently, to the conceptual and methodological shifts in the production of space, and hence in the way we think about materiality. In this context, architectural space is understood as a contingent construction – a space of engagement that appears to us as a result of continuous...... characteristics of atmosphere as a spatial phenomenon, the aim of this text is to illustrate these associations and draw out design protocols, focusing on ways in which atmosphere can be conditioned architecturally. In other words, the objective is to trace the conceptual contours of ‘atmospheric materiality’....

  1. Atmospheric Dispositifs

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2015-01-01

    , the conceptual foundations and protocols for the production of atmosphere in architecture might be found beneath the surface of contemporary debates. In this context, the notion of atmospheric dispositif – illustrated through an oeuvre of the German architect Werner Ruhnau and its theoretical and historical...... as a spatial phenomenon, exploring a multiplicity of conditions that constitute their resonant origins – i.e. the production sites from and within they have emerged. The intention is also to argue that despite the fact that atmosphere as an aesthetic category has crystallised over the last few decades...... contextualisation – provides a platform for revealing productive entanglements between heterogeneous elements, disciplines and processes. It also allows rendering atmosphere as a site of co-production open to contingencies and affective interplay on multiples levels: at the moment of its conceptualisation...

  2. Atmospheric composition

    Science.gov (United States)

    Daniels, G. E.

    1973-01-01

    The earth's atmosphere is made up of a number of gases in different relative amounts. Near sea level and up to about 90 km, the amount of these atmospheric gases in clean, relatively dry air is practically constant. Four of these gases, nitrogen, oxygen, argon, and carbon dioxide, make up 99.99 percent by volume of the atmosphere. Two gases, ozone and water vapor, change in relative amounts, but the total amount of these two is very small compared to the amount of the other gases. The atmospheric composition shown in a table can be considered valid up to 90 km geometric altitude. Above 90 km, mainly because of molecular dissociation and diffusive separation, the composition changes.

  3. Codebook-based interference alignment for uplink MIMO interference channels

    KAUST Repository

    Lee, Hyun Ho

    2014-02-01

    In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multipleoutput (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute the transmit precoder and inform its quantized index to the associated user via limited rate feedback link.We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load tomaintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF. © 2014 KICS.

  4. INTERFERENCE CANCELLATION FOR MOBILE DISPERSIVE CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Kazi Takpaya

    2003-01-01

    A robust interference canceller for Multi-Carrier Code Division Multiple Access(MC-CDMA) using Orthogonal Frequency Division Multiplexing (OFDM) in Rayleigh fading isproposed. This interference canceller is robust in the sense that it cancels Inter-Carriers Inter-ference (ICI) and is suitable for use in dispersive channels. To come up the effects of the signaldispersion, Doppler shifts and delay spreads on the performance of MC-CDMA systems over mo-bile fading channels, this interference canceller exploits the merit of the orthogonal signaling andpilot signals to evaluate the channel parameters. This interface canceller is well suited to work initerative turbo interference cancellation.

  5. Embracing interference in wireless systems

    CERN Document Server

    Gollakota, Shyamnath

    2014-01-01

    The wireless medium is a shared resource. If nearby devices transmit at thesame time, their signals interfere, resulting in a collision. In traditionalnetworks, collisions cause the loss of the transmitted information. For thisreason, wireless networks have been designed with the assumption thatinterference is intrinsically harmful and must be avoided.This book, a revised version of the author's award-winning Ph.D.dissertation, takes an alternate approach: Instead of viewing interferenceas an inherently counterproductive phenomenon that should to be avoided, wedesign practical systems that tra

  6. Interference Mitigation in Large Random Wireless Networks

    CERN Document Server

    Aldridge, Matthew

    2011-01-01

    A central problem in the operation of large wireless networks is how to deal with interference -- the unwanted signals being sent by transmitters that a receiver is not interested in. This thesis looks at ways of combating such interference. In Chapters 1 and 2, we outline the necessary information and communication theory background, including the concept of capacity. We also include an overview of a new set of schemes for dealing with interference known as interference alignment, paying special attention to a channel-state-based strategy called ergodic interference alignment. In Chapter 3, we consider the operation of large regular and random networks by treating interference as background noise. We consider the local performance of a single node, and the global performance of a very large network. In Chapter 4, we use ergodic interference alignment to derive the asymptotic sum-capacity of large random dense networks. These networks are derived from a physical model of node placement where signal strength d...

  7. Assessment of life interference in anxious children

    DEFF Research Database (Denmark)

    Rapee, Ronald; Thastum, Mikael; Chavira, Denise

    life interference derived from symptoms of anxiety. Broader and more general life interference measures tend to have minimal relevance for children with anxiety disorders. The current paper will describe two measures of life interference that have been developed at the Centre for Emotional Health...... directed at children and adolescents. One measure, the Children's Anxiety Life Interference Scale (CALIS) was developed to assess interference directly associated with symptoms of anxiety in children and adolescents, while the other, the Adolescent Life Interference Scale (ALIS) is a broader measure....... This imbalance has particularly characterised research on child anxiety where few studies have examined either the impact of anxiety disorders on children's lives or the effects of treatments on life interference. To some extent this lack of attention has come from a lack of well developed measures to assess...

  8. Cooperative Feedback for MIMO Interference Channels

    CERN Document Server

    Huang, Kaibin

    2010-01-01

    Multi-antenna precoding effectively mitigates the interference in wireless networks. However, the precoding efficiency can be significantly degraded by the overhead due to the required feedback of channel state information (CSI). This paper addresses such an issue by proposing a systematic method of designing precoders for the two-user multiple-input-multiple-output (MIMO) interference channels based on finite-rate CSI feedback from receivers to their interferers, called cooperative feedback. Specifically, each precoder is decomposed into inner and outer precoders for nulling interference and improving the data link array gain, respectively. The inner precoders are further designed to suppress residual interference resulting from finite-rate cooperative feedback. To regulate residual interference due to precoder quantization, additional scalar cooperative feedback signals are designed to control transmitters' power using different criteria including applying interference margins, maximizing sum throughput, an...

  9. Motor interference in interactive contexts

    Directory of Open Access Journals (Sweden)

    Eris eChinellato

    2015-06-01

    Full Text Available Action observation and execution share overlapping neural substrates, so that simultaneous activation by observation and execution modulates motor performance. Previous literature on simple prehension tasks has revealed that motor influence can be two-sided: facilitation for observed and performed congruent actions and interference for incongruent actions. But little is known of the specific modulations of motor performance in complex forms of interaction. Is it possible that the very same observed movement can lead either to interference or facilitation effects on a temporally overlapping congruent executed action, depending on the context? To answer this question participants were asked to perform a reach-to-grasp movement adopting a precision grip (PG while: (i observing a fixation cross, (ii observing an actor performing a PG with interactive purposes, (iii observing an actor performing a PG without interactive purposes. In particular, in the interactive condition the actor was shown trying to pour some sugar on a large cup located out of her reach but close to the participant watching the video, thus eliciting in reaction a complementary whole-hand grasp. Notably, fine-grained kinematic analysis for this condition revealed a specific delay in the grasping and reaching components and an increased trajectory deviation despite the observed and executed movement’s congruency. Moreover, early peaks of trajectory deviation seem to indicate that socially relevant stimuli are acknowledged by the motor system very early. These data suggest that interactive contexts can determine a prompt modulation of stimulus–response compatibility effects.

  10. Modal interference in spiky nanoshells.

    Science.gov (United States)

    Hastings, Simon P; Qian, Zhaoxia; Swanglap, Pattanawit; Fang, Ying; Engheta, Nader; Park, So-Jung; Link, Stephan; Fakhraai, Zahra

    2015-05-04

    Near-field enhancement of the electric field by metallic nanostructures is important in non-linear optical applications such as surface enhanced Raman scattering. One approach to producing strong localization of the electric field is to couple a dark, non-radiating plasmonic mode with a broad dipolar resonator that is detectable in the far-field. However, characterizing or predicting the degree of the coupling between these modes for a complicated nanostructure can be quite challenging. Here we develop a robust method to solve the T-matrix, the matrix that predicts the scattered electric fields of the incident light, based on finite-difference time-domain (FDTD) simulations and least square fitting algorithms. This method allows us to simultaneously calculate the T-matrix for a broad spectral range. Using this method, the coupling between the electric dipole and quadrupole modes of spiky nanoshells is evaluated. It is shown that the built-in disorder in the structure of these nanoshells allows for coupling between the dipole modes of various orientations as well as coupling between the dipole and the quadrupole modes. A coupling strength of about 5% between these modes can explain the apparent interference features observed in the single particle scattering spectrum. This effect is experimentally verified by single particle backscattering measurements of spiky nanoshells. The modal interference in disordered spiky nanoshells can explain the origin of the spectrally broad quadrupole resonances that result in strong Quadrupole Enhanced Raman Scattering (QERS) in these nanoparticles.

  11. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  12. RNA interference as a gene knockdown technique.

    Science.gov (United States)

    Shan, Ge

    2010-08-01

    Not many scientific breakthroughs bring significant advances simultaneously in both basic research and translational applications like the discovery of RNA interference. Along with the elucidation of the RNA interference pathway and the discovery of its participation in crucial biological events, a branch of science has grown to utilize the RNA interference pathway as a biotechnology for both basic and applied research. Small interference RNA, plasmid-, and virus-encoded short-hairpin RNA are now regular reagents in the tool box of biologists to knockdown the expression of specific genes posttranscriptionally. Efforts have also been made to develop RNA interference based therapeutics into reality. Many concerns about the RNA interference technique have now been answered through research and development, although hurdles are still present. In this review, the RNA interference/microRNA pathway is briefly introduced followed with a detailed summary about the design and application of the RNA interference experiments, along with examples of the utilization of the RNA interference technology in animal cells and model organisms. Recent progresses and current concerns are also highlighted. Two techniques, namely morpholino and external guide sequence, are discussed as complementary gene knockdown technology. RNA interference technology, along with several other alternative gene knockdown techniques, is now indispensable to modern biological and medical research.

  13. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  14. Ramsey Interference with Single Photons

    Science.gov (United States)

    Clemmen, Stéphane; Farsi, Alessandro; Ramelow, Sven; Gaeta, Alexander L.

    2016-11-01

    Interferometry using discrete energy levels of nuclear, atomic, or molecular systems is the foundation for a wide range of physical phenomena and enables powerful techniques such as nuclear magnetic resonance, electron spin resonance, Ramsey-based spectroscopy, and laser or maser technology. It also plays a unique role in quantum information processing as qubits may be implemented as energy superposition states of simple quantum systems. Here, we demonstrate quantum interference involving energy states of single quanta of light. In full analogy to the energy levels of atoms or nuclear spins, we implement a Ramsey interferometer with single photons. We experimentally generate energy superposition states of a single photon and manipulate them with unitary transformations to realize arbitrary projective measurements. Our approach opens the path for frequency-encoded photonic qubits in quantum information processing and quantum communication.

  15. RNA interference and antiviral therapy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    RNA interference (RNAi) is an evolutionally conserved gene silencing mechanism present in a variety of eukaryotic species. RNAi uses short double-stranded RNA (dsRNA) to trigger degradation or translation repression of homologous RNA targets in a sequence-specific manner. This system can be induced effectively in vitro and in vivo by direct application of small interfering RNAs (siRNAs), or by expression of short hairpin RNA (shRNA) with non-viral and viral vectors. To date, RNAi has been extensively used as a novel and effective tool for functional genomic studies, and has displayed great potential in treating human diseases, including human genetic and acquired disorders such as cancer and viral infections. In the present review, we focus on the recent development in the use of RNAi in the prevention and treatment of viral infections. The mechanisms,strategies, hurdles and prospects of employing RNAi in the pharmaceutical industry are also discussed.

  16. Ramsey interference with single photons

    CERN Document Server

    Clemmen, Stéphane; Ramelow, Sven; Gaeta, Alexander L

    2016-01-01

    Interferometry using discrete energy levels in nuclear, atomic or molecular systems is the foundation for a wide range of physical phenomena and enables powerful techniques such as nuclear magnetic resonance, electron spin resonance, Ramsey-based spectroscopy and laser/maser technology. It also plays a unique role in quantum information processing as qubits are realized as energy superposition states of single quantum systems. Here, we demonstrate quantum interference of different energy states of single quanta of light in full analogy to energy levels of atoms or nuclear spins and implement a Ramsey interferometer with single photons. We experimentally generate energy superposition states of a single photon and manipulate them with unitary transformations to realize arbitrary projective measurements, which allows for the realization a high-visibility single-photon Ramsey interferometer. Our approach opens the path for frequency-encoded photonic qubits in quantum information processing and quantum communicati...

  17. RNA干扰%RNA interference

    Institute of Scientific and Technical Information of China (English)

    江舸; 金由辛

    2003-01-01

    RNA干扰(RNA interference,RNAi)现象是指,当与内源性mRNA编码区某段序列同源的双链RNA(dsRNA)导入细胞后,该mRNA发生特异性的降解,而导致该基因表达的沉寂.这可能反映了生物防范病毒或转座子诱导DNA突变的一种防御机制.RNA干扰已经成为一种重要的研究基因功能的有力工具,并且有希望在对疾病的防御及治疗中发挥重要的作用.

  18. RNA干扰%RNA interference

    Institute of Scientific and Technical Information of China (English)

    陈凌; 郑祥雄

    2003-01-01

    @@ 1998年,Fire等人首次发现双链RNA(dsRNA)能够特异地抑制秀丽新小杆线虫中的纹状肌细胞unc-22基因的表达,这种抑制效能比单独应用正义或反义 RNA强十几倍;进一步研究还发现,用少量dsRNA处理的线虫就能呈现基因沉默的现象,并且该抑制现象可以传给第二代.他们将这一现象称为RNA干扰(RNA interference,RNAi)+[1].因为RNAi作用发生在转录后水平,所以又被称为转录后基因沉默(post-transcriptional gene silencing,PTGS).

  19. Suppression of Strong Background Interference on E-Nose Sensors in an Open Country Environment.

    Science.gov (United States)

    Tian, Fengchun; Zhang, Jian; Yang, Simon X; Zhao, Zhenzhen; Liang, Zhifang; Liu, Yan; Wang, Di

    2016-02-16

    The feature extraction technique for an electronic nose (e-nose) applied in tobacco smell detection in an open country/outdoor environment with periodic background strong interference is studied in this paper. Principal component analysis (PCA), Independent component analysis (ICA), re-filtering and a priori knowledge are combined to separate and suppress background interference on the e-nose. By the coefficient of multiple correlation (CMC), it can be verified that a better separation of environmental temperature, humidity, and atmospheric pressure variation related background interference factors can be obtained with ICA. By re-filtering according to the on-site interference characteristics a composite smell curve was obtained which is more related to true smell information based on the tobacco curer's experience.

  20. CDMA with interference cancellation for multiprobe missions

    Science.gov (United States)

    Divsalar, D.; Simon, M. K.

    1995-01-01

    Code division multiple-access spread spectrum has been proposed for use in future multiprobe/multispacecraft missions. This article considers a general parallel interference-cancellation scheme that significantly reduces the degradation effect of probe (user) interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each probe (user) the total interference produced by the remaining most reliably received probes (users) accessing the channel. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of probe/spacecraft interference. The one-stage interference cancellation was analyzed for two types of tentative decision devices, namely, hard and null zone decisions. Simulation results are given for one- and two-stage interference cancellation for equal as well as unequal received power probes.

  1. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  2. Atmospheric Refraction

    CERN Document Server

    Nauenberg, Michael

    2016-01-01

    Calculations of atmospheric refraction are generally based on a simplified model of atmospheric density in the troposphere which assumes that the temperature decreases at a constant lapse rate from sea level up to a height equal to eleven km, and that afterwards it remains constant. In this model, the temperature divided by the lapse rate determines the length scale in the calculations for altitudes less than this height. But daily balloon measurements across the U.S.A. reveal that in some cases the air temperature actually increases from sea level up to a height of about one km, and only after reaching a plateau, it decreases at an approximately constant lapse rate. Moreover, in three examples considered here, the temperature does not remain constant at eleven km , but continues to decreases to a minimum at about sixteen kilometers , and then increases at higher altitudes at a lower rate. Calculations of atmospheric refraction based on this atmospheric data is compared with the results of simplified models.

  3. Opportunistic Interference Alignment for Random Access Networks

    OpenAIRE

    Jin, Hu; Jeon, Sang-Woon; Jung, Bang Chul

    2015-01-01

    An interference management problem among multiple overlapped random access networks (RANs) is investigated, each of which operates with slotted ALOHA protocol. Assuming that access points and users have multiple antennas, a novel opportunistic interference alignment~(OIA) is proposed to mitigate interference among overlapped RANs. The proposed technique intelligently combines the transmit beamforming technique at the physical layer and the opportunistic packet transmission at the medium acces...

  4. Interference Coordination for Dense Wireless Networks

    DEFF Research Database (Denmark)

    Soret, Beatriz; Pedersen, Klaus I.; Jørgensen, Niels T.K.;

    2015-01-01

    The promise of ubiquitous and super-fast connectivity for the upcoming years will be in large part fulfilled by the addition of base stations and spectral aggregation. The resulting very dense networks (DenseNets) will face a number of technical challenges. Among others, the interference emerges...... simply react to an identified interference problem. As an example, we propose two algorithms to apply time domain and frequency domain small cell interference coordination in a DenseNet....

  5. Quantum interference from remotely trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, S; Rotter, D; Hennrich, M; Blatt, R [Institute for Experimental Physics, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Rohde, F; Schuck, C; Almendros, M; Gehr, R; Dubin, F; Eschner, J [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Av del Canal OlImpic, E-08860 Castelldefels (Spain)], E-mail: francois.dubin@icfo.es

    2009-01-15

    We observe quantum interference of photons emitted by two continuously laser-excited single ions, independently trapped in distinct vacuum vessels. High contrast two-photon interference is observed in two experiments with different ion species, Ca{sup +} and Ba{sup +}. Our experimental findings are quantitatively reproduced by Bloch equation calculations. In particular, we show that the coherence of the individual resonance fluorescence light field is determined from the observed interference.

  6. Using Interference to Block RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

    We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag.......We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag....

  7. Impact of MIMO Co-Channel Interference

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; De Carvalho, Elisabeth; Prasad, Ramjee

    2007-01-01

    to cellular interference of some specific Multiple Input Multiple Output (MIMO) schemes on the same and other MIMO schemes. The goal is to study the impact of interference from MIMO schemes at a user located in the cell edge. Semi-Analytical evaluations of Signal to Interference and Noise Ratio (SINR) is done...... to find out the SINR statistics of different combinations of desired and interfering links. We have studied linear combining receivers for all the link combinations. Based on the current analysis, it is found that Space-Time Block Code (STBC) is a severe interferer compared to others, and specific...

  8. Electromagnetic Interference (EMI) and TEMPEST Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Electromagnetic Interference (EMI), Electromagnetic Compatibility (EMC) and TEMPEST testing are conducted at EPG's Blacktail Canyon Test Facility in one of its two...

  9. Interference Alignment Using Variational Mean Field Annealing

    DEFF Research Database (Denmark)

    Badiu, Mihai Alin; Guillaud, Maxime; Fleury, Bernard Henri

    2014-01-01

    We study the problem of interference alignment in the multiple-input multiple- output interference channel. Aiming at minimizing the interference leakage power relative to the receiver noise level, we use the deterministic annealing approach to solve the optimization problem. In the corresponding...... for interference alignment. We also show that the iterative leakage minimization algorithm by Gomadam et al. and the alternating minimization algorithm by Peters and Heath, Jr. are instances of our method. Finally, we assess the performance of the proposed algorithm through computer simulations....

  10. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    -dynamic discontinuities, the intensities corresponding to the transition from regular to irregular interference were described. Numerical calculations of the shock-wave structure transformation in the conditions of hysteresis were performed. The results were compared with the experiments carried out by hydraulic analogy method. Practical significance. Results of the work complement well the theory of stationary gas-dynamic discontinuities interference and can be used at designing of perspective images of supersonic and hypersonic aircraft.

  11. Atmospheric Neutrinos

    CERN Document Server

    Gaisser, Thomas K

    2016-01-01

    In view of the observation by IceCube of high-energy astrophysical neutrinos, it is important to quantify the uncertainty in the background of atmospheric neutrinos. There are two sources of uncertainty, the imperfect knowledge of the spectrum and composition of the primary cosmic rays that produce the neutrinos and the limited understanding of hadron production, including charm, at high energy. This paper is an overview of both aspects.

  12. Is There Semantic Interference in Delayed Naming?

    Science.gov (United States)

    Madebach, Andreas; Oppermann, Frank; Hantsch, Ansgar; Curda, Christian; Jescheniak, Jorg D.

    2011-01-01

    The semantic interference effect in the picture-word interference task is interpreted as an index of lexical competition in prominent speech production models. Janssen, Schirm, Mahon, and Caramazza (2008) challenged this interpretation on the basis of experiments with a novel version of this task, which introduced a task-switching component.…

  13. Partial interference subspace rejection in CDMA systems

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiene; Mewelstein, Paul

    2001-01-01

    Previously presented interference subspace rejection (ISR) proposed a family of new efficient multiuser detectors for CDMA. We reconsider in this paper the modes of ISR using decision feedback (DF). DF modes share similarities with parallel interference cancellation (PIC) but attempt to cancel...

  14. 47 CFR 74.604 - Interference avoidance.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference avoidance. 74.604 Section 74.604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... Stations § 74.604 Interference avoidance. (a) (b) Where two or more licensees are assigned a common...

  15. Interference and the Law of Energy Conservation

    Science.gov (United States)

    Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

    2014-01-01

    Introductory physics textbooks consider interference to be a process of redistribution of energy from the wave sources in the surrounding space resulting in constructive and destructive interferences. As one can expect, the total energy flux is conserved. However, one case of apparent non-conservation energy attracts great attention. Imagine that…

  16. The Nature and Diagnosis of Interference Phenomena.

    Science.gov (United States)

    Denison, Norman

    1966-01-01

    The recognition of the systematic nature of the interference of the mother tongue when learning a second language is among the most significant advances in linguistics for the teaching and learning of foreign languages. The work of Weinreich showed that interference between language systems--the absorption of loan words, calques, and phonological,…

  17. Optimal interference code based on machine learning

    Science.gov (United States)

    Qian, Ye; Chen, Qian; Hu, Xiaobo; Cao, Ercong; Qian, Weixian; Gu, Guohua

    2016-10-01

    In this paper, we analyze the characteristics of pseudo-random code, by the case of m sequence. Depending on the description of coding theory, we introduce the jamming methods. We simulate the interference effect or probability model by the means of MATLAB to consolidate. In accordance with the length of decoding time the adversary spends, we find out the optimal formula and optimal coefficients based on machine learning, then we get the new optimal interference code. First, when it comes to the phase of recognition, this study judges the effect of interference by the way of simulating the length of time over the decoding period of laser seeker. Then, we use laser active deception jamming simulate interference process in the tracking phase in the next block. In this study we choose the method of laser active deception jamming. In order to improve the performance of the interference, this paper simulates the model by MATLAB software. We find out the least number of pulse intervals which must be received, then we can make the conclusion that the precise interval number of the laser pointer for m sequence encoding. In order to find the shortest space, we make the choice of the greatest common divisor method. Then, combining with the coding regularity that has been found before, we restore pulse interval of pseudo-random code, which has been already received. Finally, we can control the time period of laser interference, get the optimal interference code, and also increase the probability of interference as well.

  18. Spin Interference in Rashba 2DEG Systems

    Science.gov (United States)

    Nitta, Junsaku

    The gate controllable SOI provides useful information about spin interference.1 Spin interference effects are studied in two different interference loop structures. It is known that sample specific conductance fluctuations affect the conductance in the interference loop. By using array of many interference loops, we carefully pick up TRS Altshuler-Aronov-Spivak (AAS)-type oscillation which is not sample specific and depends on the spin phase. The experimentally obtained gate voltage dependence of AAS oscillations indicates that the spin precession angle can be controlled by the gate voltage.2 We demonstrate the time reversal Aharonov-Casher (AC) effect in small arrays of mesoscopic rings.3 By using an electrostatic gate we can control the spin precession angle rate and follow the AC phase over several interference periods. We also see the second harmonic of the AC interference, oscillating with half the period. The spin interference is still visible after more than 20π precession angle. We have proposed a Stern-Gerlach type spin filter based on the Rashba SOI.4 A spatial gradient of effective magnetic field due to the nonuniform SOI separates spin up and down electrons. This spin filter works even without any external magnetic fields and ferromagnetic contacts. We show the semiconductor/ferromagnet hybrid structure is an effective way to detect magnetization process of submicron magnets. The problem of the spin injection from ferromagnetic contact into 2DEG is also disicussed. Note from Publisher: This article contains the abstract only.

  19. Alternative splicing interference by xenobiotics.

    Science.gov (United States)

    Zaharieva, Emanuela; Chipman, J Kevin; Soller, Matthias

    2012-06-14

    The protein coding sequence of most eukaryotic genes (exons) is interrupted by non-coding parts (introns), which are excised in a process termed splicing. To generate a mature messenger RNA (mRNA) hundreds of combinatorial protein-protein and RNA-protein interactions are required to splice out often very large introns with high fidelity and accuracy. Inherent to splicing is the use of alternative splice sites generating immense proteomic diversity from a limited number of genes. In humans, alternative splicing is a major mode of regulating gene expression, occurs in over 90% of genes and is particularly abundant in the brain. Only recently, it has been recognized that the complexity of the splicing process makes it susceptible to interference by various xenobiotics. These compounds include antineoplastic substances, commonly used drugs and food supplements and cause a spectrum of effects ranging from deleterious inhibition of general splicing to highly specific modifications of alternative splicing affecting only certain genes. Alterations in splicing have been implicated in numerous diseases such as cancer and neurodegeneration. Splicing regulation plays an important role in the execution of programmed cell death. The switch between anti- and pro-apoptotic isoforms by alternative splice site selection and misregulation of a number of splicing factors impacts on cell survival and disease. Here, our current knowledge is summarized on compounds interfering with general and alternative splicing and of the current methodology to study changes in these processes relevant to the field of toxicology and future risk assessments.

  20. Interference Channels with Strong Secrecy

    CERN Document Server

    He, Xiang

    2009-01-01

    It is known that given the real sum of two independent uniformly distributed lattice points from the same nested lattice codebook, the eavesdropper can obtain at most 1 bit of information per channel regarding the value of one of the lattice points. In this work, we study the effect of this 1 bit information on the equivocation expressed in three commonly used information theoretic measures, i.e., the Shannon entropy, the Renyi entropy and the min entropy. We then demonstrate its applications in an interference channel with a confidential message. In our previous work, we showed that nested lattice codes can outperform Gaussian codes for this channel when the achieved rate is measured with the weak secrecy notion. Here, with the Renyi entropy and the min entropy measure, we prove that the same secure degree of freedom is achievable with the strong secrecy notion as well. A major benefit of the new coding scheme is that the strong secrecy is generated from a single lattice point instead of a sequence of lattic...

  1. ``Quantum'' interference with bouncing drops

    Science.gov (United States)

    Bohr, Tomas; Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens

    2013-11-01

    In a series of recent papers (most recently) Yves Couder and collaborators have explored the dynamics of walking drops on the surface of a vibrated bath of silicon oil and have demonstrated a close analogy to quantum phenomena. The bouncing drop together with the surface wave that it excites seems to be very similar to the pilot wave envisaged by de Broglie for quantum particles. In particular, have studied a double slit experiment with walking drops, where an interference pattern identical to the quantum version is found even though it is possible to follow the orbits of the drops and unambigously determine which slit it goes through, something which in quantum mechanics would be ruled out by the Heisenberg uncertainly relations. We have repeated the experiment and present a somewhat more complicated picture. Theoretically, we study a Schrödinger equation with a source term originating from a localised ``particle'' being simultaneously guided by the wave. We present simple solutions to such a field theory and discuss the fundamental difficulties met by such a theory in order to comply with quantum mechanics.

  2. Exotic tracers for atmospheric studies

    Energy Technology Data Exchange (ETDEWEB)

    Lovelock, J.E. (Brazzos Ltd., Launceston (UK)); Ferber, G.J. (National Oceanic and Atmospheric Administration, Silver Spring, MD (USA). Air Resources Lab.)

    1982-01-01

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximise research benefits.

  3. Exotic tracers for atmospheric studies

    Science.gov (United States)

    Lovelock, James E.; Ferber, Gilbert J.

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximize research benefits.

  4. Laser self-mixing interference fiber sensor

    Institute of Scientific and Technical Information of China (English)

    Zhu Jun; Zhao Yan; Jin Guo-fan

    2008-01-01

    Fibre sensors exhibit a number of advantages over other sensors such as high sensitivity, electric insulation, corrosion resistance, interference rejection and so on. And laser elf-mixing interference can accurately detect the phase difference of feedback light. In this paper, a novel laser self-mixing interference fibre sensor that combines the advantages of fibre sensors with those of laser self-mixing interference is presented. Experimental configurations are set up to study the relationship between laser power output and phase of laser feedback light when the fibre trembles or when the fibre is stretched or pressed. The theoretical analysis of pressure sensors based on laser self-mixing interference is indicated to accord with the experimental results.

  5. Periods of weed interference in cowpea

    Directory of Open Access Journals (Sweden)

    Maria José Pinheiro Corrêa

    2015-12-01

    Full Text Available This work aimed to determine the periods weed interference in cowpea. The experimental design was randomized blocks, and the treatments consisted of periods of control or coexistence with the culture. The periods of control or weed coexistence after culture emergence were: 0-10, 0-20, 0-30, 0-40, 0-50, 0-60 and 0 – 80 days after crop emergence. The main weed density were: AlternantheratenellaColla,CyperusrotundusL., Digitariaciliaris(Retz. Koeler, Eleusineindica(L.Gaertn,MollugoverticillataL.Considering 5% of tolerance in cowpea yield reduction, the period prior interference was 8 days after emergence (DAE, total period of interference prevention was 53 DAE and critical period of interference prevention between 8 and 53 DAE. Weed interference reduced the grainyield up to 46%.

  6. Improved CDMA Performance Using Parallel Interference Cancellation

    Science.gov (United States)

    Simon, Marvin; Divsalar, Dariush

    1995-01-01

    This report considers a general parallel interference cancellation scheme that significantly reduces the degradation effect of user interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each user the interference produced by the remaining users accessing the channel in an amount proportional to their reliability. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of user interference. The 1-stage interference cancellation is analyzed for three types of tentative decision devices, namely, hard, null zone, and soft decision, and two types of user power distribution, namely, equal and unequal powers. Simulation results are given for a multitude of different situations, in particular, those cases for which the analysis is too complex.

  7. Phonon-Mediated Nonclassical Interference in Diamond

    Science.gov (United States)

    England, Duncan G.; Fisher, Kent A. G.; MacLean, Jean-Philippe W.; Bustard, Philip J.; Heshami, Khabat; Resch, Kevin J.; Sussman, Benjamin J.

    2016-08-01

    Quantum interference of single photons is a fundamental aspect of many photonic quantum processing and communication protocols. Interference requires that the multiple pathways through an interferometer be temporally indistinguishable to within the coherence time of the photon. In this Letter, we use a diamond quantum memory to demonstrate interference between quantum pathways, initially temporally separated by many multiples of the optical coherence time. The quantum memory can be viewed as a light-matter beam splitter, mapping a THz-bandwidth single photon to a variable superposition of the output optical mode and stored phononic mode. Because the memory acts both as a beam splitter and as a buffer, the relevant coherence time for interference is not that of the photon, but rather that of the memory. We use this mechanism to demonstrate nonclassical single-photon and two-photon interference between quantum pathways initially separated by several picoseconds, even though the duration of the photons themselves is just ˜250 fs .

  8. Interference Alignment for Clustered Multicell Joint Decoding

    CERN Document Server

    Chatzinotas, Symeon

    2010-01-01

    Multicell joint processing has been proven to be very efficient in overcoming the interference-limited nature of the cellular paradigm. However, for reasons of practical implementation global multicell joint decoding is not feasible and thus clusters of cooperating Base Stations have to be considered. In this context, intercluster interference has to be mitigated in order to harvest the full potential of multicell joint processing. In this paper, four scenarios of intercluster interference are investigated, namely a) global multicell joint processing, b) interference alignment, c) resource division multiple access and d) cochannel interference allowance. Each scenario is modelled and analyzed using the per-cell ergodic sum-rate capacity as a figure of merit. In this process, a number of theorems are derived for analytically expressing the asymptotic eigenvalue distributions of the channel covariance matrices. The analysis is based on principles from Free Probability theory and especially properties in the R a...

  9. Understanding quantum interference in General Nonlocality

    CERN Document Server

    Wanng, Hai-Jhun

    2010-01-01

    In this paper we attempt to give an understanding of quantum double-slit interference of fermions in the framework of General Nonlocality (GN) [J. Math. Phys. 49, 033513 (2008)] by studying the self-interaction of matter wave. From the metric of the GN, we derive a special formalism to interpret the interference contrast when the self-interaction is perturbative. According to the formalism, the characteristic of interference pattern is in agreement with experiment qualitatively. As examples, we apply the formalism to the cases governed by Schr\\"odinger current and Dirac current respectively, both of which are relevant to topology. The gap between these two cases corresponds to a spin-current effect, which is possible to test in the near future. In addition, a general interference formalism for both perturbative and non-perturbative self-interactions is presented. By analyzing the general formalism we predict that in the nonperturbative limit there is no interference at all.

  10. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    . As a response to this situation, our design artefact, the interactive furniture Kidkit, invites children to become accustomed to the alarming sounds sampled from the ward while they are waiting in the waiting room. Our design acknowledges how atmospheres emerge as temporal negotiations between the rhythms......, a familiar relationship with the alarming sounds in the ward, enabling her to focus later more on the visit with the relative. The article discusses the proposed design strategy behind this solution and the potentiality for its use in hospital environments in general....

  11. Multimode Hong-Ou-Mandel interference

    CERN Document Server

    Walborn, S P; Pádua, S; Monken, C H

    2003-01-01

    We consider multimode two-photon interference at a beam splitter by photons created by spontaneous parametric down-conversion. The resulting interference pattern is shown to depend upon the transverse spatial symmetry of the pump beam. In an experiment, we employ the first-order Hermite-Gaussian modes in order to show that, by manipulating the pump beam, one can control the resulting two-photon interference behavior. We expect these results to play an important role in the engineering of quantum states of light for use in quantum information processing and quantum imaging.

  12. Fano interference in two-photon transport

    Science.gov (United States)

    Xu, Shanshan; Fan, Shanhui

    2016-10-01

    We present a general input-output formalism for the few-photon transport in multiple waveguide channels coupled to a local cavity. Using this formalism, we study the effect of Fano interference in two-photon quantum transport. We show that the physics of Fano interference can manifest as an asymmetric spectral line shape in the frequency dependence of the two-photon correlation function. The two-photon fluorescence spectrum, on the other hand, does not exhibit the physics of Fano interference.

  13. Multiple Beam Interference in a Relativistic Medium

    CERN Document Server

    Rakshit, Supantho

    2016-01-01

    In this paper the effects of movement of optical medium on the conditions of interference, transmission pattern and performance of spectroscopes like Febry Perot are investigated. Firstly, the conditions of constructive and destructive interference of two beams in a moving thin film is derived. Then the idea is expanded to multiple beam interference and a new modified equation of the transmission pattern is formulated with the help of basic Lorentz transformation of space and time co-ordinates and electromagnetic field. Further the new effective resolving power of a Febry Perot spectroscope is determined using this idea, which has a moving dielectric medium in its etalon.

  14. Wave and Particle in Molecular Interference Lithography

    CERN Document Server

    Juffmann, Thomas; Geyer, Philipp; Major, Andras G; Deachapunya, Sarayut; Ulbricht, Hendrik; Arndt, Markus; 10.1103/PhysRevLett.103.263601

    2010-01-01

    The wave-particle duality of massive objects is a cornerstone of quantum physics and a key property of many modern tools such as electron microscopy, neutron diffraction or atom interferometry. Here we report on the first experimental demonstration of quantum interference lithography with complex molecules. Molecular matter-wave interference patterns are deposited onto a reconstructed Si(111) 7x7 surface and imaged using scanning tunneling microscopy. Thereby both the particle and the quantum wave character of the molecules can be visualized in one and the same image. This new approach to nanolithography therefore also represents a sensitive new detection scheme for quantum interference experiments.

  15. Wave and particle in molecular interference lithography.

    Science.gov (United States)

    Juffmann, Thomas; Truppe, Stefan; Geyer, Philipp; Major, András G; Deachapunya, Sarayut; Ulbricht, Hendrik; Arndt, Markus

    2009-12-31

    The wave-particle duality of massive objects is a cornerstone of quantum physics and a key property of many modern tools such as electron microscopy, neutron diffraction or atom interferometry. Here we report on the first experimental demonstration of quantum interference lithography with complex molecules. Molecular matter-wave interference patterns are deposited onto a reconstructed Si(111) 7x7 surface and imaged using scanning tunneling microscopy. Thereby both the particle and the quantum wave character of the molecules can be visualized in one and the same image. This new approach to nanolithography therefore also represents a sensitive new detection scheme for quantum interference experiments.

  16. Inter-WBAN Coexistence and Interference Mitigation

    Institute of Scientific and Technical Information of China (English)

    Bin Liu; Xiaosong Zhao; Lei Zou; Chang Wen Chen

    2015-01-01

    With promising applications in e⁃health and entertainment, wireless body area networks (WBANs) have attracted the in⁃terest of both academia and industry. If WBANs are densely deployed within a small area, serious problems may arise be⁃tween the WBANs. In this paper, we discuss issues related to the coexistence of WBANs and investigate the main fac⁃tors that cause inter⁃WBAN interference. We survey inter⁃WBAN interference mitigation strategies and track recent re⁃search developments. We also discuss unresolved issues re⁃lated to inter⁃WBAN interference mitigation and propose fu⁃ture research directions.

  17. CORRELATED INTERFERENCE CANCELLATION FOR IR-UWB

    Institute of Scientific and Technical Information of China (English)

    Zhang Zaichen; Yu Xutao; Bi Guangguo

    2008-01-01

    In this letter,we propose a hybrid analog/digital detection algorithm,the Correlated Interference Cancellation (CIC) algorithm,for Impulse Radio Ultra-WideBand (IR-UWB) system. The CIC algorithm correlates received signal with its delayed versions in the analog domain and samples the correlation output at the symbol rate. The symbol rate samples are processed in the digital domain to perform interference cancellation. Therefore,CIC works for high data rate systems with heavy InterSymbol Interference (ISI). Simulation results show that CIC achieves good performance in typical UWB channels.

  18. MIMO Networks: the Effects of Interference

    CERN Document Server

    Chiani, Marco; Shin, Hyundong

    2008-01-01

    Multiple-input/multiple-output (MIMO) systems promise enormous capacity increase and are being considered as one of the key technologies for future wireless networks. However, the decrease in capacity due to the presence of interferers in MIMO networks is not well understood. In this paper, we develop an analytical framework to characterize the capacity of MIMO communication systems in the presence of multiple MIMO co-channel interferers and noise. We consider the situation in which transmitters have no information about the channel and all links undergo Rayleigh fading. We first generalize the known determinant representation of hypergeometric functions with matrix arguments to the case when the argument matrices have eigenvalues of arbitrary multiplicity. This enables the derivation of the ergodic capacity expressions for MIMO systems in the presence of multiple MIMO interferers. Our analysis is valid for any number of interferers, each with arbitrary number of antennas having possibly unequal power levels....

  19. Exploiting Genetic Interference for Antiviral Therapy.

    Science.gov (United States)

    Tanner, Elizabeth J; Kirkegaard, Karla A; Weinberger, Leor S

    2016-05-01

    Rapidly evolving viruses are a major threat to human health. Such viruses are often highly pathogenic (e.g., influenza virus, HIV, Ebola virus) and routinely circumvent therapeutic intervention through mutational escape. Error-prone genome replication generates heterogeneous viral populations that rapidly adapt to new selection pressures, leading to resistance that emerges with treatment. However, population heterogeneity bears a cost: when multiple viral variants replicate within a cell, they can potentially interfere with each other, lowering viral fitness. This genetic interference can be exploited for antiviral strategies, either by taking advantage of a virus's inherent genetic diversity or through generating de novo interference by engineering a competing genome. Here, we discuss two such antiviral strategies, dominant drug targeting and therapeutic interfering particles. Both strategies harness the power of genetic interference to surmount two particularly vexing obstacles-the evolution of drug resistance and targeting therapy to high-risk populations-both of which impede treatment in resource-poor settings.

  20. Fight plant pests using RNA interference

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ CAS plant physiologists have recently invented a plant-mediated RNA interference (RNAi) technique to effectively and specifically control the gene expression of the cotton bollworm (Helicoverpa armigera) and stunt its growth.

  1. Radio VLBI and the quantum interference paradox

    CERN Document Server

    Singal, Ashok K

    2016-01-01

    We address here the question of interference of radio signals from astronomical sources like distant quasars, in a very long baseline interferometer (VLBI), where two (or more) distantly located radio telescopes (apertures), receive simultaneous signal from the sky. In an equivalent optical two-slit experiment, it is generally argued that for the photons involved in the interference pattern on the screen, it is not possible, even in principle, to ascertain which of the two slits a particular photon went through. It is argued that any procedure to ascertain this destroys the interference pattern. But in the case of the modern radio VLBI, it is a routine matter to record the phase and amplitude of the voltage outputs from the two radio antennas on a recording media separately and then do the correlation between the two recorded signals later in an offline manner. Does this not violate the quantum interference principle? We provide a resolution of this problem here.

  2. Parallel interference cancellation for CDMA applications

    Science.gov (United States)

    Divsalar, Dariush (Inventor); Simon, Marvin K. (Inventor); Raphaeli, Dan (Inventor)

    1997-01-01

    The present invention provides a method of decoding a spread spectrum composite signal, the composite signal comprising plural user signals that have been spread with plural respective codes, wherein each coded signal is despread, averaged to produce a signal value, analyzed to produce a tentative decision, respread, summed with other respread signals to produce combined interference signals, the method comprising scaling the combined interference signals with a weighting factor to produce a scaled combined interference signal, scaling the composite signal with the weighting factor to produce a scaled composite signal, scaling the signal value by the complement of the weighting factor to produce a leakage signal, combining the scaled composite signal, the scaled combined interference signal and the leakage signal to produce an estimate of a respective user signal.

  3. Grassmannian Differential Limited Feedback for Interference Alignment

    CERN Document Server

    Ayach, Omar El

    2011-01-01

    Channel state information (CSI) in the interference channel can be used to precode, align, and reduce the dimension of interference at the receivers, to achieve the channel's maximum multiplexing gain, through what is known as interference alignment. Most interference alignment algorithms require knowledge of all the interfering channels to compute the alignment precoders. CSI, considered available at the receivers, can be shared with the transmitters via limited feedback. When alignment is done by coding over frequency extensions in a single antenna system, the required CSI lies on the Grassmannian manifold and its structure can be exploited in feedback. Unfortunately, the number of channels to be shared grows with the square of the number of users creating too much overhead with conventional feedback methods. This paper proposes Grassmannian differential feedback to reduce feedback overhead by exploiting both the channel's temporal correlation and Grassmannian structure. The performance of the proposed algo...

  4. Conducted Electromagnetic Interference (EMI) in Smart Grids

    CERN Document Server

    Smolenski, Robert

    2012-01-01

    As power systems develop to incorporate renewable energy sources, the delivery systems may be disrupted by the changes involved. The grid’s technology and management must be developed to form Smart Grids between consumers, suppliers and producers. Conducted Electromagnetic Interference (EMI) in Smart Grids considers the specific side effects related to electromagnetic interference (EMI) generated by the application of these Smart Grids. Conducted Electromagnetic Interference (EMI) in Smart Grids presents specific EMI conducted phenomena as well as effective methods to filter and handle them once identified. After introduction to Smart Grids, the following sections cover dedicated methods for EMI reduction and potential avenues for future development including chapters dedicated to: •potential system services, •descriptions of the EMI spectra shaping methods, •methods of interference voltage compensation, and theoretical analysis of experimental results.  By focusing on these key aspects, Conducted El...

  5. Automotive radar - investigation of mutual interference mechanisms

    Science.gov (United States)

    Goppelt, M.; Blöcher, H.-L.; Menzel, W.

    2010-09-01

    In the past mutual interference between automotive radar sensors has not been regarded as a major problem. With an increasing number of such systems, however, this topic is receiving more and more attention. The investigation of mutual interference and countermeasures is therefore one topic of the joint project "Radar on Chip for Cars" (RoCC) funded by the German Federal Ministry of Education and Research (BMBF). RoCC's goal is to pave the way for the development of high-performance, low-cost 79 GHz radar sensors based on Silicon-Germanium (SiGe) Monolithic Microwave Integrated Circuits (MMICs). This paper will present some generic interference scenarios and report on the current status of the analysis of interference mechanisms.

  6. Interference Alignment via Improved Subspace Conditioning

    CERN Document Server

    Kim, Douglas

    2010-01-01

    For the K user, single input single output (SISO), frequency selective interference channel, a new low complexity transmit beamforming design that improves the achievable sum rate is presented. Jointly employing the interference alignment (IA) scheme presented by Cadambe and Jafar in [1] and linear minimum mean square error (MMSE) decoding at the transmitters and receivers, respectively, the new IA precoding design improves the average sum rate while preserving the achievable degrees of freedom of the Cadambe and Jafar scheme, K/2.

  7. Fading and interference mitigation in wireless communications

    CERN Document Server

    Panic, Stefan; Anastasov, Jelena; Spalevic, Petar

    2013-01-01

    The rapid advancement of various wireless communication system services has created the need to analyze the possibility of their performance improvement. Introducing the basic principles of digital communications performance analysis and its mathematical formalization, Fading and Interference Mitigation in Wireless Communications will help you stay up to date with recent developments in the performance analysis of space diversity reception over fading channels in the presence of cochannel interference.The book presents a unified method for computing the performance of digital communication sys

  8. Test Anxiety: Cognitive Interference or Inadequate Preparation

    Science.gov (United States)

    1990-08-01

    anxiety interferes with students’ recall of prior learning on examinations. This so called interference model has recently been challenged by an...instructions, sometimes called ego involving instructions, suggesting that performance on the research task is related to students’ ability or school...New York: Irvington Press. Culler, R. E., & Holahan , C. (1980). Test taking and academic performance: The effects of study-related behaviors

  9. Interference Cancellation System Design Using GNU Radio

    Science.gov (United States)

    2015-12-01

    ARL-TR-7546 ● DEC 2015 US Army Research Laboratory Interference Cancellation System Design Using GNU Radio by Jan Paolo...Interference Cancellation System Design Using GNU Radio by Jan Paolo Acosta Sensors and Electron Devices Directorate, ARL...Design Using GNU Radio 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Jan Paolo Acosta 5d. PROJECT NUMBER

  10. Investigation of Interference Models for RFID Systems

    Directory of Open Access Journals (Sweden)

    Linchao Zhang

    2016-02-01

    Full Text Available The reader-to-reader collision in an RFID system is a challenging problem for communications technology. In order to model the interference between RFID readers, different interference models have been proposed, mainly based on two approaches: single and additive interference. The former only considers the interference from one reader within a certain range, whereas the latter takes into account the sum of all of the simultaneous interferences in order to emulate a more realistic behavior. Although the difference between the two approaches has been theoretically analyzed in previous research, their effects on the estimated performance of the reader-to-reader anti-collision protocols have not yet been investigated. In this paper, the influence of the interference model on the anti-collision protocols is studied by simulating a representative state-of-the-art protocol. The results presented in this paper highlight that the use of additive models, although more computationally intensive, is mandatory to improve the performance of anti-collision protocols.

  11. Cross-limb interference during motor learning.

    Directory of Open Access Journals (Sweden)

    Benedikt Lauber

    Full Text Available It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we investigate if this interference effect can also be observed in the limb contralateral to the trained one. Therefore, five different groups practiced a ballistic finger flexion task followed by an interfering visuomotor accuracy task with the same limb. Performance in the ballistic task was tested before the training, after the training and in an immediate retention test after the practice of the interference task for both the trained and the untrained hand. After training, subjects showed not only significant learning and interference effects for the trained limb but also for the contralateral untrained limb. Importantly, the interference effect in the untrained limb was dependent on the level of skill acquisition in the interfering motor task. These behavioural results of the untrained limb were accompanied by training specific changes in corticospinal excitability, which increased for the hemisphere ipsilateral to the trained hand following ballistic training and decreased during accuracy training of the ipsilateral hand. The results demonstrate that contralateral interference effects may occur, and that interference depends on the level of skill acquisition in the interfering motor task. This finding might be particularly relevant for rehabilitation.

  12. Planning projects for generation of electrical energy in the state of Sao Paulo, according to the degree of interference on air quality: an atmospheric qualification index using fuzzy sets; Ordenamento de projetos de geracao de energia eletrica no estado de Sao Paulo, segundo o grau de interferencia na qualidade do ar: um indice de qualificacao atmosferica (IQA) utilizando fuzzy sets

    Energy Technology Data Exchange (ETDEWEB)

    Dzedzej, Maira; Maciel, Jonas Fernandes; Santos, Afonso Henrique Moreira [IX Consultoria e Representacoes Ltda, Itajuba, MG (Brazil); Duarte, Pamella Santos [MS Consultoria Ltda, Itajuba, MG (Brazil); Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

    2010-07-01

    Environmental issues are of great importance when assessing the feasibility and priority installation of new developments in electric power generation. In this sense, fuzzy logic can help define the regions that have favorable characteristics for receiving certain forms of generation. This study sought to order for the State of Sao Paulo, four kinds of generation projects: those using municipal solid waste gasification, those which make use of landfill gas with a change in firing (to reduce emissions), thermoelectric plants (TEPs) to bagasse (with 15% straw) and Small Hydropower (SHP). Such an ordering considered not only the type of generation but also the allocation of projects in the four regions, defined by regional vocations as defined by the State Water Resources Plan (Annex III of the State Law No. 9.034/94): Agriculture, Conservation, In Industrialization and Industrial. As a result, the use of fuzzy sets allowed the creation of a ranking of the alternatives (which totaled 14 possibilities), based exclusively on the degree of interference in air quality resulting from the installation of every form of generation. Such information may help the decision-making governing bodies to establish priorities in order, thereby accelerating the process of installation and operation of projects for generating electricity. (author)

  13. Outage analysis of interference-limited systems using STBC with co-channel MIMO interferers

    Institute of Scientific and Technical Information of China (English)

    Yongzhao LI; Leonard J.CIMINI,JR.; Nageen HIMAYAT

    2009-01-01

    The performance of Space-Time Block Coding (STBC) with co-channel MIMO interference is investigated.For an interference-limited environment, the closed-form ex-pressions for the probability density functions of the signal-to-interference ratio are derived and applied to analyze the outage probability with three typical types of co-channel MIMO interferers: STBC, open-loop spatial multiplexing and closed-loop spatial multiplexing. Both theoretical anal-yses and simulation results show that the performance of STBC is independent of the MIMO modes used in the in-terfering links.

  14. Polarized line transfer with F-state interference in a non-magnetic medium: Partial frequency redistribution effects in the collisionless regime

    CERN Document Server

    Smitha, H N; Nagendra, K N; Sampoorna, M; Stenflo, J O

    2012-01-01

    Quantum interference phenomena manifests itself in several ways in the polarized solar spectrum formed due to coherent scattering processes. One such effect arises due to interference between the fine structure (J) states giving rise to multiplets. Another effect is that which arises due to interference between the hyperfine structure (F) states. We extend the redistribution matrix derived for the J-state interference to the case of F-state interference. We then incorporate it into the polarized radiative transfer equation and solve it for isothermal constant property slab atmospheres. The relevant transfer equation is solved using a polarized approximate lambda iteration (PALI) technique based on operator perturbation. An alternative method derived from the Neumann series expansion is also proposed and is found to be relatively more efficient than the PALI method. The effects of PRD and the F-state interference on the shapes of the linearly polarized Stokes profiles are discussed. The emergent Stokes profile...

  15. The research of the precoding matrices of interference alignment

    Science.gov (United States)

    Du, Yuelin; Xue, Jiang

    2017-01-01

    In recent years, with the rapid development of wireless communication industry, how to manage the interference become a central problem in modern communication system. Actually, this problem mostly comes from the less and less spectrum resource and increasing demand for high data rates. Although many interference management techniques have been proposed, because the interference can exist in any part of wireless communication, some basic problems of network interference are not able to be solved until the emergence of interference alignment technology. Interference alignment, in theory, can enable a performance that all the interference signals fall into the subspace of interference and all the useful signal also fall into the corresponding subspace. In this paper, we focus on the problem of signal transmitted over an interference channel, along the lines of the recently proposed methods of interference alignment. From the basic principle of interference alignment, we can see each receiver maintains its corresponding subspace, the transmitters mold their transmissions regularly in order to make all the interference signal received by a particular receiver and then falls into its interference subspace. The remaining part of the receiver space can be used to get the useful signal. For the general interference channel, compared with the previous method, this kind of technique not only minimizes the interference power that is overflowed out the interference subspace, but also minimizes the power of useful signal that is fell into the interference subspace.

  16. Interference effects and phase sensitivity in hearing.

    Science.gov (United States)

    Moore, Brian C J

    2002-05-15

    This paper reviews interference effects in the auditory system, particularly effects occurring in the outer ear and the inner ear (cochlea). Sounds enter the ear canal both directly and after reflections from the pinna. This results in complex spectral patterns, which vary systematically with the direction of incidence of the sound source relative to the head. Evidence is described indicating that these spectral patterns are used in the localization of sounds in space. The cochlea behaves like a limited-resolution frequency analyser. When the components of a complex sound are closely spaced in frequency, they can interfere on the basilar membrane (BM) within the cochlea. Interference effects on the BM are complex, as they are influenced by a physiologically active mechanism which introduces strong nonlinearities, including level-dependent amplification. Interference effects on the BM play a role in many aspects of auditory perception, including the perception of consonance and dissonance, the perception of pitch, the perception of changes in phase, and the perception of timbre. Interference effects in the cochlea may also play a role in producing the spectral regularity observed in sounds reflected from the ear (otoacoustic emissions).

  17. General Quantum Interference Principle and Duality Computer

    Institute of Scientific and Technical Information of China (English)

    LONG Gui-Lu

    2006-01-01

    In this article, we propose a general principle of quantum interference for quantum system, and based on this we propose a new type of computing machine, the duality computer, that may outperform in principle both classical computer and the quantum computer. According to the general principle of quantum interference, the very essence of quantum interference is the interference of thesub-waves of the quantum system itself. A quantum system considered here can be any quantum system: a single microscopic particle, a composite quantum system such as an atom or a molecule, or a loose collection of a few quantum objects such as two independent photons. In the duality computer,the wave of the duality computer is split into several sub-waves and they pass through different routes, where different computing gate operations are performed. These sub-waves are then re-combined to interfere to give the computational results. The quantum computer, however, has only used the particle nature of quantum object. In a duality computer,it may be possible to find a marked item from an unsorted database using only a single query, and all NP-complete problems may have polynomial algorithms. Two proof-of-the-principle designs of the duality computer are presented:the giant molecule scheme and the nonlinear quantum optics scheme. We also propose thought experiment to check the related fundamental issues, the measurement efficiency of a partial wave function.

  18. Disentangling posterror and postconflict reduction of interference.

    Science.gov (United States)

    Van der Borght, Liesbet; Braem, Senne; Notebaert, Wim

    2014-12-01

    Conflict monitoring theory (CMT; Botvinick, Braver, Barch, Carter, & Cohen Psychological Review, 108, 624-652, 2001) states that response conflict, the simultaneous activation of two competing responses, increases task focus and reduces interference from irrelevant information. CMT also defines errors as conflict, and reduced interference effects have consistently been reported following errors (Ridderinkhof Psychological Research, 66, 312-323, 2002). However, previous computations of this posterror reduction of interference (PERI) have overlooked the congruency of the previous trial. This is problematic, because most errors are made on incongruent trials, creating a confound between (previous) accuracy and (previous) congruency. Therefore, it is likely that reduced interference following errors is in fact the congruency sequence effect (i.e., reduced interference following incongruent, relative to congruent, trials). Our results corroborate this idea by demonstrating that participants indeed showed significant PERI following a congruent trial, but inverse PERI following an incongruent trial. These findings are discussed in light of the adaptation-by-binding account (Verguts & Notebaert Psychological Review, 115, 518-525, 2008, Trends in Cognitive Sciences, 13, 252-257, 2009).

  19. Autobiographical thinking interferes with episodic memory consolidation.

    Directory of Open Access Journals (Sweden)

    Michael Craig

    Full Text Available New episodic memories are retained better if learning is followed by a few minutes of wakeful rest than by the encoding of novel external information. Novel encoding is said to interfere with the consolidation of recently acquired episodic memories. Here we report four experiments in which we examined whether autobiographical thinking, i.e. an 'internal' memory activity, also interferes with episodic memory consolidation. Participants were presented with three wordlists consisting of common nouns; one list was followed by wakeful rest, one by novel picture encoding and one by autobiographical retrieval/future imagination, cued by concrete sounds. Both novel encoding and autobiographical retrieval/future imagination lowered wordlist retention significantly. Follow-up experiments demonstrated that the interference by our cued autobiographical retrieval/future imagination delay condition could not be accounted for by the sound cues alone or by executive retrieval processes. Moreover, our results demonstrated evidence of a temporal gradient of interference across experiments. Thus, we propose that rich autobiographical retrieval/future imagination hampers the consolidation of recently acquired episodic memories and that such interference is particularly likely in the presence of external concrete cues.

  20. Epulis and pyogenic granuloma with occlusal interference

    Directory of Open Access Journals (Sweden)

    Widowati Witjaksono

    2005-06-01

    Full Text Available In dental clinic of Hospital University Science Malaysia (HUSM, there were cases with Localized Gingival Enlargement (LGE in the oral cavity with occlusal interference. In this study, three cases were observed. They were a 13 - year- old female with fibrous lge around 31 and 32 with occlusal interference in protrusive movement due to X bite, a 15 - year – old female with pyogenic granuloma near 11 & 21 with occlusal interference due to deep bite; and a 24 – year – old female who was eight months in pregnancy with pyogenic granuloma on the 34-35 and severe generalized pregnancy gingivitis with occlusal interference in centric occlusion and lateral movement. Clinical and histopathological diagnosis of the first case showed fibrous epulis, whereas the second and third cases disclosed pyogenic granuloma. Chronic trauma of the gingiva due to occlusal interference was assumed to be the cause of those LGE in case 1 and 2, while in case 3 poor oral hygiene and chronic trauma were assumed to be the etiologic factors.

  1. Delaying Interference Training Has Equivalent Effects in Various Pavlovian Interference Paradigms

    Science.gov (United States)

    Powell, Elizabeth J.; Escobar, Martha; Kimble, Whitney

    2013-01-01

    Spontaneous recovery in extinction appears to be inversely related to the acquisition-to-extinction interval, but it remains unclear why this is the case. Rat subjects trained with one of three interference paradigms exhibited less spontaneous recovery of the original response after delayed than immediate interference, regardless of whether…

  2. Reading Ability Is Negatively Related to Stroop Interference

    Science.gov (United States)

    Protopapas, Athanassios; Archonti, Anastasia; Skaloumbakas, Christos

    2007-01-01

    Stroop interference is often taken as evidence for reading automaticity even though young and poor readers, who presumably lack reading automaticity, present strong interference. Here the relationship between reading skills and Stroop interference was studied in a 7th-grade sample. Greater interference was observed in children diagnosed with…

  3. Collisional quantum interference on rotational energy transfer: physical interpretation of the differential interference angle

    Institute of Scientific and Technical Information of China (English)

    Li Yong-Qing; Li Jian; Ma Feng-Cai

    2006-01-01

    Collisional quantum interference (CQI) on the intramolecular rotational energy transfer is observed in an experiment with a static cell, and the integral interference angles are measured. To obtain more accurate information, an experiment with a molecular beam is carried out, and thereby the relationship between the differential interference angle and the scattering angle is obtained. Based on the first-Born approximation of time-dependent perturbation theory,the theoretical model of CQI is developed in an atom-diatom system in the condition of the molecular beam, with the long-range interaction potential taken into account. The method of measuring correctly the differential interference angle is presented. The tendencies of the differential interference angle changing with the impact parameter and relative velocity are discussed. The theoretical model presented here is important for understanding or performing the experiment in the molecular beam.

  4. Interference Calculus A General Framework for Interference Management and Network Utility Optimization

    CERN Document Server

    Schubert, Martin

    2012-01-01

    This book develops a mathematical framework for modeling and optimizing interference-coupled multiuser systems. At the core of this framework is the concept of general interference functions, which provides a simple means of characterizing interdependencies between users. The entire analysis builds on the two core axioms scale-invariance and monotonicity. The proposed network calculus has its roots in power control theory and wireless communications. It adds theoretical tools for analyzing the typical behavior of interference-coupled networks. In this way it complements existing game-theoretic approaches. The framework should also be viewed in conjunction with optimization theory. There is a fruitful interplay between the theory of interference functions and convex optimization theory. By jointly exploiting the properties of interference functions, it is possible to design algorithms that outperform general-purpose techniques that only exploit convexity. The title “network calculus” refers to the fact tha...

  5. Wind interference between two high-rise building models: On the influence of shielding, channeling and buffeting on peak pressures

    NARCIS (Netherlands)

    Bronkhorst, A.J.; Geurts, C.P.W.; Bentum, C.A. van; Blocken, B.

    2014-01-01

    The influence of interference between two high-rise building models on the minimum peak pressures was investigated in an atmospheric boundary layer wind tunnel. Pressure measur€ments were performed on a square model with an aspect ratio of 1 to 4. The influence of an interfering model with the same

  6. Transverse relativistic effects in paraxial wave interference

    CERN Document Server

    Bliokh, Konstantin Y; Nori, Franco

    2013-01-01

    We consider relativistic deformations of interfering paraxial waves moving in the transverse direction. Owing to superluminal transverse phase velocities, noticeable deformations of the interference patterns arise when the waves move with respect to each other with non-relativistic velocities. Similar distortions also appear on a mutual tilt of the interfering waves, which causes a phase delay analogous to the relativistic time delay. We illustrate these observations by the interference between a vortex wave beam and a plane wave, which exhibits a pronounced deformation of the radial fringes into a fork-like pattern (relativistic Hall effect). Furthermore, we describe an additional relativistic motion of the interference fringes (a counter-rotation in the vortex case), which become noticeable at the same non-relativistic velocities.

  7. Cross-limb Interference during motor learning

    DEFF Research Database (Denmark)

    Lauber, Benedikt; Jensen, Jesper Lundbye; Keller, Martin;

    2013-01-01

    the training, after the training and in an immediate retention test after the practice of the interference task for both the trained and the untrained hand. After training, subjects showed not only significant learning and interference effects for the trained limb but also for the contralateral untrained limb......It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we...... investigate if this interference effect can also be observed in the limb contralateral to the trained one. Therefore, five different groups practiced a ballistic finger flexion task followed by an interfering visuomotor accuracy task with the same limb. Performance in the ballistic task was tested before...

  8. Multichannel interference mitigation methods in radio astronomy

    CERN Document Server

    Leshem, A; Boonstra, A J; Leshem, Amir; Veen, Alle-Jan van der; Boonstra, Albert-Jan

    2000-01-01

    Radio-astronomical observations are increasingly corrupted by RF interference, and online detection and filtering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the astronomical problem in an array signal processing language, and give an introduction to some elementary algorithms from that field. We consider two topics in detail: interference detection by rank estimation of short-term covariance matrices, and spatial filtering by subspace estimation and projection. We discuss experimental data collected at the Westerbork radio telescope, and illustrate the effectiveness of the space-time detection and blanking process on the recovery of a 3C48 absorption line in the presence of GSM mobile telephony interference.

  9. Cross-limb Interference during motor learning

    DEFF Research Database (Denmark)

    Lauber, Benedikt; Jensen, Jesper Lundbye; Keller, Martin

    2013-01-01

    It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we....... Importantly, the interference effect in the untrained limb was dependent on the level of skill acquisition in the interfering motor task. These behavioural results of the untrained limb were accompanied by training specific changes in corticospinal excitability, which increased for the hemisphere ipsilateral...... to the trained hand following ballistic training and decreased during accuracy training of the ipsilateral hand. The results demonstrate that contralateral interference effects may occur, and that interference depends on the level of skill acquisition in the interfering motor task. This finding might...

  10. On Interference of Chinese with ELL

    Institute of Scientific and Technical Information of China (English)

    九曼

    2011-01-01

    It is popularly admitted that the foreign language learning is strongly influenced by learners' first language.Generally speaking,the interference of Chinese with ELL is divided into negative transfer and positive transfer,which are manifested at various levels during ELL.The thesis aims to show the interference of Chinese with ELL,with the approach of qualitative analysis,the paper is arranged into Part Ⅰ:Introduction; Part Ⅱ:The Contrast between ELL and Chinese Language Acquisition; Part Ⅲ:The Influence of Chinese on ELL:Part Ⅵ:Conclusion.Being aware of the interference of Chinese with ELL will help students overcome the obstacles and promote ELL.

  11. Electromagnetic Interference on Large Wind Turbines

    Directory of Open Access Journals (Sweden)

    Florian Krug

    2009-11-01

    Full Text Available Electromagnetic interference (EMI can both affect and be transmitted by mega-watt wind turbines. This paper provides a general overview on EMI with respect to mega-watt wind turbines. Possibilities of measuring all types of electromagnetic interference are shown. Electromagnetic fields resulting from a GSM transmitter mounted on a mega-watt wind turbine will be analyzed in detail. This cellular system operates as a real-time communication link. The method-of-moments is used to analytically describe the electro-magnetic fields. The electromagnetic interference will be analyzed under the given boundary condition with a commercial simulation tool. Different transmitter positions are judged on the basis of their radiation patterns. The principal EMI mechanisms are described and taken into consideration.

  12. Gravitational and rotational effects in quantum interference

    Energy Technology Data Exchange (ETDEWEB)

    Anandan, J.

    1977-03-15

    The phase shift due to gravitation and rotation in the quantum interference of two coherent beams is obtained relativistically and compared with the recent experiment of Colella, Overhauser, and Werner. A general expression relating the quantum phase shift to the transverse acceleration of a classical particle in the plane of interference for an arbitrary interaction with any external field is given. This can serve as a correspondence principle between quantum physics and classical physics. The phase shift due to the coupling of spin to curvature of space-time is deduced and written explicitly for the special case of a Schwarzschild field. The last result implies that a massless spinning particle can have at most two helicity states and its world line in a gravitational field is a null geodesic. Finally, new experiments are proposed to test the effect of rotation on quantum interference and to obtain direct evidence of the equivalence principle in quantum mechanics.

  13. Non-classical paths in interference experiments

    CERN Document Server

    Sawant, Rahul; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-01-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well known text books in quantum mechanics implicitly and/or explicitly use this assumption which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in quantum interference experiments which provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  14. Nonclassical Paths in Quantum Interference Experiments

    Science.gov (United States)

    Sawant, Rahul; Samuel, Joseph; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-09-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well-known text books in quantum mechanics implicitly and/or explicitly use this assumption that is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from nonclassical paths in quantum interference experiments that provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these nonclassical paths is difficult to present. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  15. Effects of optical interference and annealing on the performance of poly (3-hexylthiophene):fullerene based solar cells

    Institute of Scientific and Technical Information of China (English)

    You Hai-Long; Zhang Chun-Fu

    2009-01-01

    In this paper, the effects of optical interference and annealing on the performance of P3HT:PCBM based organic solar cells are studied in detail. Due to the optical interference effect, short circuit current density (JSC) shows obvious oscillatory behaviour with the variation of active layer thickness. With the help of the simulated results, the devices are optimized around the first two optical interference peaks. It is found that the optimized thicknesses are 80 and 208 nm. The study on the effect of annealing on the performance indicates that post-annealing is more favourable than pre-annealing. Based on post-annealing, different annealing temperatures are tested. The optimized annealing condition is 160℃ for 10 min in a nitrogen atmosphere. The device shows that the open circuit voltage VOC achieves about 0.65V and the power conversion efficiency is as high as 4.0 % around the second interference peak.

  16. Frequent video game players resist perceptual interference.

    Directory of Open Access Journals (Sweden)

    Aaron V Berard

    Full Text Available Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT, a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning.

  17. Neutrino tridents and W - Z interference

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, S.R.; Rabinowitz, S.A.; Arroyo, C.; Bachmann, K.T.; Blair, R.E.; Foudas, C.; King, B.J.; Lefmann, W.C.; Leung, W.C.; Oltman, E.; Quintas, P.Z.; Sciulli, F.J.; Seligman, B.G.; Shaevitz, M.H. (Columbia University, New York, New York 10027 (USA)); Merritt, F.S.; Oreglia, M.J.; Schumm, B.A. (University of Chicago, Chicago, Illinois 60637 (USA)); Bernstein, R.H.; Borcherding, F.; Fisk, H.E.; Lamm, M.J.; Marsh, W.; Merritt, K.W.B.; Schellman, H.; Yovanovitch, D.D. (Fermilab, Batavia, Illinois 60510 (USA)); Bodek, A.; Budd, H.S.; de Barbaro, P.; Sakumoto, W.K. (University of Rochester, Rochester, New York 14627 (USA)); Sandler, P.H.; Smith, W.H. (University of Wisconsin, Madison, Wisconsin 53706 (USA))

    1991-06-17

    We present a measurement of neutrino tridents, muon pairs induced by neutrino scattering in the Coulomb field of a target nucleus, in the Columbia-Chicago-Fermilab-Rochester neutrino experiment at the Fermilab Tevatron. The observed number of tridents after geometric and kinematic corrections, 37.0{plus minus}12.4, supports the standard-model prediction of 45.3{plus minus}2.3 events. This is the first demonstration of the {ital W}-{ital Z} destructive interference from neutrino tridents, and rules out, at 99% C.L., the {ital V}-{ital A} prediction without the interference.

  18. LANGUAGE AND CULTURE INTERFERENCE IN PLURILINGUAL EDUCATION

    Directory of Open Access Journals (Sweden)

    Hackett-Jones, A.V.

    2016-09-01

    Full Text Available The article deals with interlingual phenomena that occur in the process of multiple language acquisition in a learning environment. The notions of language interference and transfer put forward by the theories of bilingualism, give useful insights when applied to the modern day educational trends. Language and culture interference is an important aspect to be considered with regard to teaching of plurilingual learners, whose communicative competence is formed on the basis of several linguistic and cultural systems that interact with each other and exert mutual influence.

  19. Carbon nanostructure composite for electromagnetic interference shielding

    Indian Academy of Sciences (India)

    Anupama Joshi; Suwarna Datar

    2015-06-01

    This communication reviews current developments in carbon nanostructure-based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference. Conventionally, metal-based shielding materials have been used. But due to the requirement of light weight, corrosion resistive materials, lot of work is being done on composite materials. In this research the forerunner is the nanocarbon-based composite material whose different forms add different characteristics to the composite. The article focusses on composites based on graphene, graphene oxide, carbon nanotubes, and several other novel forms of carbon.

  20. Interference of electromagnetic waves in dynamic metabolism

    Institute of Scientific and Technical Information of China (English)

    黄卡玛; 唐敬贤; 刘永清; 徐兰

    1995-01-01

    Life is a continuous process of the dynamic metabolism.The influence of electromagneticwaves on the process of metabolism cannot be neglected.Here a new theory of electromagnetic interference inthe dynamic metabolism of life is proposed.The statistical dynamic equations of ion and free radical in thebiochemical reaction radiated by electromagnetic waves are given.The intensity of electromagnetic interferencecould be described with an interference factor.Good agreement can be seen between the calculated and meas-ured results for a famous experiment of radio-frequency radiation-induced calcium ion efflux enhancement.

  1. Atmosphere: Power, Critique, Politics

    DEFF Research Database (Denmark)

    Albertsen, Niels

    2016-01-01

    This paper hans three interrelated parts. First, atmosphere is approached through the concept of power. Atmospheres 'grip' us directly or mediate power indirectly by manipulating moods and evoking emotions. How does atmosphere relate to different conceptions of power? Second, atmospheric powers m...... be critiqued. Which conception of critique can be involved? Third, critiquing atmospheric powers can generate political conflict. How does atmospheric disputes relate to conceptions of politics and the political?...

  2. Two-order Interference of Single Photon

    Institute of Scientific and Technical Information of China (English)

    JIANG Yunkun; LI Jian; SHI Baosen; FAN Xiaofeng; GUO Guangcan

    2000-01-01

    A pair of photons called signal and idler photons, respectively, are produced through the nonlinear process of type-I spontaneous parametric downconversion in BBO crystal pumped by the second-harmonic wave of a Ti:sapphire femtosecond laser pulse. The two-order interference phenomenon of the signal photon in Michelson interferometer is observed and give an analysis in detail.

  3. Phase-Modulation Laser Interference Microscopy

    DEFF Research Database (Denmark)

    Brazhe, Alexey; Brazhe, Nadezda; Maximov, G. V.

    2008-01-01

    We describe how phase-modulation laser interference microscopy and wavelet analysis can be applied to noninvasive nonstained visualization and study of the structural and dynamical properties of living cells. We show how phase images of erythrocytes can reveal the difference between various...

  4. Interference subspace rejection in wideband CDMA:

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiene; Mermelstein, Paul

    2001-01-01

    This paper extends our study on a multi-user receiver structure for base-station receivers with antenna arrays in multicellular systems. The receiver employs a beamforming structure with constraints that nulls the signal component in appropriate interference subspaces. Here we introduce a new mod...

  5. Movement Interference in Autism-Spectrum Disorder

    Science.gov (United States)

    Gowen, E.; Stanley, J.; Miall, R. C.

    2008-01-01

    Movement interference occurs when concurrently observing and executing incompatible actions and is believed to be due to co-activation of conflicting populations of mirror neurons. It has also been suggested that mirror neurons contribute towards the imitation of observed actions. However, the exact neural substrate of imitation may depend on task…

  6. Wakeful rest alleviates interference-based forgetting.

    Science.gov (United States)

    Mercer, Tom

    2015-01-01

    Retroactive interference (RI)--the disruptive influence of events occurring after the formation of a new memory--is one of the primary causes of forgetting. Placing individuals within an environment that postpones interference should, therefore, greatly reduce the likelihood of information being lost from memory. For example, a short period of wakeful rest should diminish interference-based forgetting. To test this hypothesis, participants took part in a foreign language learning activity and were shown English translations of 20 Icelandic words for immediate recall. Half of the participants were then given an 8-min rest before completing a similar or dissimilar interfering distractor task. The other half did not receive a rest until after the distractor task, at which point interference had already taken place. All participants were then asked to translate the Icelandic words for a second time. Results revealed that retention was significantly worse at the second recall test, but being allowed a brief rest before completing the distractor task helped reduce the amount of forgetting. Taking a short, passive break can shield new memories from RI and alleviate forgetting.

  7. Jam-X: Wireless Agreement under Interference

    CERN Document Server

    Boano, Carlo Alberto; Zúñiga, Marco Antonio; Voigt, Thiemo

    2012-01-01

    Wireless low-power transceivers used in sensor networks such as IEEE 802.15.4 typically operate in unlicensed frequency bands that are subject to external interference from devices transmitting at much higher power. Communication protocols should therefore be designed to be robust against such interference. A critical building block of many protocols at all layers is agreement on a piece of information among a set of nodes. At the MAC layer, nodes may need to agree on a new time slot or frequency channel; at the application layer nodes may need to agree on handing over a leader role from one node to another. Message loss caused by interference may break agreement in two different ways: none of the nodes use the new information (time slot, channel, leader) and stick with the previous assignment, or - even worse - some nodes use the new information and some do not. This may lead to reduced performance or failures. In this paper we investigate the problem of agreement under interference and point out the limitat...

  8. The Acceptability of Speech with Radio Interference

    DEFF Research Database (Denmark)

    Baykaner, K.; Hummersone, H.; Mason, R.;

    2014-01-01

    A listening test was conducted to investigate the acceptability of audio-on-audio interference for radio programs featuring speech as the target. Twenty-one subjects, including naïve and expert listeners, were presented with 200 randomly assigned pairs of stimuli and asked to report, for each trial...

  9. Engine Power Effects on Support Interference

    NARCIS (Netherlands)

    Horsten, B.J.C.; Veldhuis, L.L.M.

    2009-01-01

    Renewed interest in propeller propulsion on aircraft configurations combined with higher propeller loads lead to the question how the effects of the propulsion on model support disturbances should be accounted for. In this paper, the determination of engine power effects on support interference of s

  10. Electron Interference in Ballistic Graphene Nanoconstrictions

    DEFF Research Database (Denmark)

    Baringhaus, Jens; Settnes, Mikkel; Aprojanz, Johannes

    2016-01-01

    We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed...

  11. Preserved Proactive Interference in Autism Spectrum Disorder

    Science.gov (United States)

    Carmo, Joana C.; Duarte, Elsa; Pinho, Sandra; Filipe, Carlos N.; Marques, J. Frederico

    2016-01-01

    In this study, we aimed to evaluate further the functioning and structuring of the semantic system in autism spectrum disorders (ASD). We analyzed the performance of 19 high-functioning young adults with ASD and a group of 20 age-, verbal IQ- and education-matched individuals with the Proactive Interference (PI) Paradigm to evaluate semantic…

  12. 47 CFR 74.703 - Interference.

    Science.gov (United States)

    2010-10-01

    ... due to terrain shielding and/or Longley-Rice terrain dependent propagation methods, the licensee of a... any condition of interference to the direct reception of the signal of any other TV broadcast analog... of a regularly used signal is impaired by the signals radiated by the low power TV, TV translator,...

  13. Nonsurgical management of disc-interference disorders.

    Science.gov (United States)

    Okeson, J P

    1991-01-01

    Disc-interference disorders are a group of intracapsular problems that make up one category of temporomandibular disorders. The dental profession's understanding of these disorders has changed greatly in recent years. This article reviews current concepts regarding the diagnosis and management of these disorders as revealed through recent clinical studies.

  14. Interference effects of categorization on decision making.

    Science.gov (United States)

    Wang, Zheng; Busemeyer, Jerome R

    2016-05-01

    Many decision making tasks in life involve a categorization process, but the effects of categorization on subsequent decision making has rarely been studied. This issue was explored in three experiments (N=721), in which participants were shown a face stimulus on each trial and performed variations of categorization-decision tasks. On C-D trials, they categorized the stimulus and then made an action decision; on X-D trials, they were told the category and then made an action decision; on D-alone trials, they only made an action decision. An interference effect emerged in some of the conditions, such that the probability of an action on the D-alone trials (i.e., when there was no explicit categorization before the decision) differed from the total probability of the same action on the C-D or X-D trials (i.e., when there was explicit categorization before the decision). Interference effects are important because they indicate a violation of the classical law of total probability, which is assumed by many cognitive models. Across all three experiments, a complex pattern of interference effects systematically occurred for different types of stimuli and for different types of categorization-decision tasks. These interference effects present a challenge for traditional cognitive models, such as Markov and signal detection models, but a quantum cognition model, called the belief-action entanglement (BAE) model, predicted that these results could occur. The BAE model employs the quantum principles of superposition and entanglement to explain the psychological mechanisms underlying the puzzling interference effects. The model can be applied to many important and practical categorization-decision situations in life.

  15. The differential interference angle in collisional quantum interference on rotational energy transfer

    Institute of Scientific and Technical Information of China (English)

    Wang Wei-Li; Miao Gang; Chen Yue-Hui; Tang Dan; Ma Feng-Cai

    2008-01-01

    Collisional quantum interference (CQI) in the intramolecular rotational energy transfer was observed in experiment by Sha and co-workers.[1] The interference angle, which measuring the degree of the coherence, were measured in the experiment of the static cell. Based on the first Born approximation of time dependent perturbation theory, taking into accounts the anisotropic Lennard-Jones interaction potentials, this paper describes the theoretical model of CQI in intramolecular rotational energy transfer in an atom-diatom collision system. In the model, the differential interference angle for the experiment of the molecular beam is calculated, the changing tendencies of the differential interference angle with the impact parameter and collision partners are obtained. This theoretical model is important for understanding or performing this kind of experiments.

  16. Elements of Cellular Blind Interference Alignment --- Aligned Frequency Reuse, Wireless Index Coding and Interference Diversity

    CERN Document Server

    Jafar, Syed A

    2012-01-01

    We explore degrees of freedom (DoF) characterizations of partially connected wireless networks, especially cellular networks, with no channel state information at the transmitters. Specifically, we introduce three fundamental elements --- aligned frequency reuse, wireless index coding and interference diversity --- through a series of examples, focusing first on infinite regular arrays, then on finite clusters with arbitrary connectivity and message sets, and finally on heterogeneous settings with asymmetric multiple antenna configurations. Aligned frequency reuse refers to the optimality of orthogonal resource allocations in many cases, but according to unconventional reuse patterns that are guided by interference alignment principles. Wireless index coding highlights both the intimate connection between the index coding problem and cellular blind interference alignment, as well as the added complexity inherent to wireless settings. Interference diversity refers to the observation that in a wireless network ...

  17. Feedback-Topology Designs for Interference Alignment in MIMO Interference Channels

    CERN Document Server

    Cho, Sungyoon; Huang, Kaibin; Kim, Dongku; Lau, Vincent K N; Seo, Hanbyul; Kim, Byounghoon

    2011-01-01

    Interference alignment (IA) is a joint-transmission technique that achieves the capacity of the interference channel for high signal-to-noise ratios (SNRs). Most prior work on IA is based on the impractical assumption that perfect and global channel-state information(CSI) is available at all transmitters. To implement IA, each receiver has to feed back CSI to all interferers, resulting in overwhelming feedback overhead. In particular, the sum feedback rate of each receiver scales quadratically with the number of users even if the quantized CSI is fed back. To substantially suppress feedback overhead, this paper focuses on designing efficient arrangements of feedback links, called feedback topologies, under the IA constraint. For the multiple-input-multiple-output (MIMO) K-user interference channel, we propose the feedback topology that supports sequential CSI exchange (feedback and feedforward) between transmitters and receivers so as to achieve IA progressively. This feedback topology is shown to reduce the ...

  18. Receive Diversity and Ergodic Performance of Interference Alignment on the MIMO Gaussian Interference Channel

    CERN Document Server

    Guillaud, Maxime

    2010-01-01

    We consider interference alignment (IA) over K-user Gaussian MIMO interference channel (MIMO-IC) when the SNR is not asymptotically high. We introduce a generalization of IA which enables receive diversity inside the interference-free subspace. We generalize the existence criterion of an IA solution proposed by Yetis et al. to this case, thereby establishing a multi-user diversity-multiplexing trade-off (DMT) for the interference channel. Furthermore, we derive a closed-form tight lower-bound for the ergodic mutual information achievable using IA over a Gaussian MIMO-IC with Gaussian i.i.d. channel coefficients at arbitrary SNR, when the transmitted signals are white inside the subspace defined by IA. Finally, as an application of the previous results, we compare the performance achievable by IA at various operating points allowed by the DMT, to a recently introduced distributed method based on game theory.

  19. Communication in a Poisson Field of Interferers -- Part II: Channel Capacity and Interference Spectrum

    CERN Document Server

    Pinto, Pedro C

    2010-01-01

    In Part I of this paper, we presented a mathematical model for communication subject to both network interference and noise, where the interferers are scattered according to a spatial Poisson process, and are operating asynchronously in a wireless environment subject to path loss, shadowing, and multipath fading. We determined the distribution of the aggregate interference and the error performance of the link. In this second part, we characterize the capacity of the link subject to both network interference and noise. Then, we put forth the concept of spectral outage probability (SOP), a new characterization of the aggregate radio-frequency emission generated by communicating nodes in a wireless network. We present some applications of the SOP, namely the establishment of spectral regulations and the design of covert military networks. The proposed framework captures all the essential physical parameters that affect the aggregate network emission, yet is simple enough to provide insights that may be of value...

  20. Interference of speckle patterns projected by multimode fibers

    Science.gov (United States)

    Lomer, M.; Rodriguez-Cobo, L.; Madruga, F.; Lopez-Higuera, J. M.

    2015-08-01

    In this paper, the interference speckle patterns generated by multimode optical fibers are described. In our experience two types of interference are present, random interference between modes propagated in the fiber that give rise to speckle pattern, and not random speckle interference patterns using a Michelson interferometer generating a pattern of conventional interference. Multimode fibers using different materials and core radii have been obtained interference patterns quality characteristic reducing the effects of modal noise in fiber speckle patterns. Experimental results and their potential applications are presented.

  1. Reliability Estimations of Control Systems Effected by Several Interference Sources

    Institute of Scientific and Technical Information of China (English)

    DengBei-xing; JiangMing-hu; LiXing

    2003-01-01

    In order to establish the sufficient and necessary condition that arbitrarily reliable systems can not be constructed with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of interference sources are raised respectively: interference source possessing real input vectors and constant reliable interferen cesource. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbitrarily reliable systems can not be constructed with the elements effected by above interference sources.

  2. Interference tables: a useful model for interference analysis in asynchronous multicarrier transmission

    Science.gov (United States)

    Medjahdi, Yahia; Terré, Michel; Ruyet, Didier Le; Roviras, Daniel

    2014-12-01

    In this paper, we investigate the impact of timing asynchronism on the performance of multicarrier techniques in a spectrum coexistence context. Two multicarrier schemes are considered: cyclic prefix-based orthogonal frequency division multiplexing (CP-OFDM) with a rectangular pulse shape and filter bank-based multicarrier (FBMC) with physical layer for dynamic spectrum access and cognitive radio (PHYDYAS) and isotropic orthogonal transform algorithm (IOTA) waveforms. First, we present the general concept of the so-called power spectral density (PSD)-based interference tables which are commonly used for multicarrier interference characterization in spectrum sharing context. After highlighting the limits of this approach, we propose a new family of interference tables called `instantaneous interference tables'. The proposed tables give the interference power caused by a given interfering subcarrier on a victim one, not only as a function of the spectral distance separating both subcarriers but also with respect to the timing misalignment between the subcarrier holders. In contrast to the PSD-based interference tables, the accuracy of the proposed tables has been validated through different simulation results. Furthermore, due to the better frequency localization of both PHYDYAS and IOTA waveforms, FBMC technique is demonstrated to be more robust to timing asynchronism compared to OFDM one. Such a result makes FBMC a potential candidate for the physical layer of future cognitive radio systems.

  3. The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

    KAUST Repository

    Chaaban, Anas

    2016-03-01

    The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

  4. (Sub-)Optimality of Treating Interference as Noise in the Cellular Uplink With Weak Interference

    KAUST Repository

    Gherekhloo, Soheil

    2015-11-09

    Despite the simplicity of the scheme of treating interference as noise (TIN), it was shown to be sum-capacity optimal in the Gaussian interference channel (IC) with very-weak (noisy) interference. In this paper, the two-user IC is altered by introducing an additional transmitter that wants to communicate with one of the receivers of the IC. The resulting network thus consists of a point-to-point channel interfering with a multiple access channel (MAC) and is denoted by PIMAC. The sum-capacity of the PIMAC is studied with main focus on the optimality of TIN. It turns out that TIN in its naive variant, where all transmitters are active and both receivers use TIN for decoding, is not the best choice for the PIMAC. In fact, a scheme that combines both time division multiple access and TIN (TDMA-TIN) strictly outperforms the naive-TIN scheme. Furthermore, it is shown that in some regimes, TDMA-TIN achieves the sum-capacity for the deterministic PIMAC and the sum-capacity within a constant gap for the Gaussian PIMAC. In addition, it is shown that, even for very-weak interference, there are some regimes where a combination of interference alignment with power control and TIN at the receiver side outperforms TDMA-TIN. As a consequence, on the one hand, TIN in a cellular uplink is approximately optimal in certain regimes. On the other hand, those regimes cannot be simply described by the strength of interference.

  5. Interferences in photolytic NO2 measurements: explanation for an apparent missing oxidant?

    Science.gov (United States)

    Reed, Chris; Evans, Mathew J.; Di Carlo, Piero; Lee, James D.; Carpenter, Lucy J.

    2016-04-01

    Measurement of NO2 at low concentrations (tens of ppts) is non-trivial. A variety of techniques exist, with the conversion of NO2 into NO followed by chemiluminescent detection of NO being prevalent. Historically this conversion has used a catalytic approach (molybdenum); however, this has been plagued with interferences. More recently, photolytic conversion based on UV-LED irradiation of a reaction cell has been used. Although this appears to be robust there have been a range of observations in low-NOx environments which have measured higher NO2 concentrations than might be expected from steady-state analysis of simultaneously measured NO, O3, jNO2, etc. A range of explanations exist in the literature, most of which focus on an unknown and unmeasured "compound X" that is able to convert NO to NO2 selectively. Here we explore in the laboratory the interference on the photolytic NO2 measurements from the thermal decomposition of peroxyacetyl nitrate (PAN) within the photolysis cell. We find that approximately 5 % of the PAN decomposes within the instrument, providing a potentially significant interference. We parameterize the decomposition in terms of the temperature of the light source, the ambient temperature, and a mixing timescale ( ˜ 0.4 s for our instrument) and expand the parametric analysis to other atmospheric compounds that decompose readily to NO2 (HO2NO2, N2O5, CH3O2NO2, IONO2, BrONO2, higher PANs). We apply these parameters to the output of a global atmospheric model (GEOS-Chem) to investigate the global impact of this interference on (1) the NO2 measurements and (2) the NO2 : NO ratio, i.e. the Leighton relationship. We find that there are significant interferences in cold regions with low NOx concentrations such as the Antarctic, the remote Southern Hemisphere, and the upper troposphere. Although this interference is likely instrument-specific, the thermal decomposition to NO2 within the instrument's photolysis cell could give an at least partial

  6. Interference and Chaos in Metamaterials Cavities

    Science.gov (United States)

    Litchinitser, Natalia; Jose, Jorge

    2014-03-01

    Optical metamaterials are engineered artificial nanostructures that possess optical properties not available in nature. As metamaterials research continues to mature, their practical applications as well as fundamental questions on wave propagation in these materials attract significant interest. In this talk we focus on wave propagation and interference in chaotic wave cavities with negative or near-zero index of refraction and in double-slit configurations. In this context, we explicitly consider an incomplete two-dimensional D-cavity previously studied, which shows chaotic ray propagation together with scars. We have addressed the question as to how that type of wave propagation is modified by adding metamaterials in these chaotic cavities. We find that the wave interference patterns show significant qualitatively and quantitative changes depending on the effective parameters of the cavity, illumination conditions (planes waves versus beams), and geometry of the system. We will discuss possible experimental setups where these results may be validated.

  7. A chirp modem incorporating interference excision

    Science.gov (United States)

    Darbyshire, E. P.; Gott, G. F.

    1992-08-01

    The paper describes an experimental 75-baud chirp modem designed to operate at high frequency (HF), which is able to reject interference from other HF users by adaptive filtering at the receiver. It also has inherently good performance in multipath preparation and in white noise, and is thus capable of robust digital communication. The system has been tested over a 170 km point-to-point HF skywave link, in which short chirp messages (approximately 30 s duration) were alternated in time with frequency-exchange keyed (FEK) messages. The total duration of the tests was 72 hours, and included day and night operation. In these tests, the chirp system had an overall performance which was superior to that of FEK. FEK occasionally suffered from long periods (e.g., 1 hour) of severe failure, essentially due to interference, whereas the chirp modem achieved more continuous useful operation.

  8. Topological Mass Generation as an Interference Phenomenon

    CERN Document Server

    Ilha, A; Ilha, Anderson; Wotzasek, Clovis

    2000-01-01

    It is proposed a new mechanism for the phenomenon of topological mass generation in three spacetime dimensions as the result of the interference of two opposite massless chiral modes. This mechanism, already used to produce the massive vectorial mode of the 2D Schwinger model, is here exploited to produce the gauge invariant massive mode of the Maxwell-Chern-Simons theory. Moreover the procedure is clearly dimensionally independent: a new chiral boson action is proposed for odd and even dimensional space-times to be used as the basic building blocks of the interference schemes. This is a new result that extends the two-dimensional Floreanini-Jackiw action to higher dimensional spaces and is in clear contrast with the twice odd dimensional chiral form extensions.

  9. Interference Phenomenon for Different Chiral Bosonization Schemes

    CERN Document Server

    Abreu, Everton M C; Abreu, Everton M C; Wotzasek, Clovis

    1998-01-01

    We study the relationship between different chiral bosonization schemes (CBS) in the context of the soldering formalism\\cite{MS}, that considers the phenomenon of interference in the quantum field theory\\cite{ABW}. This analysis is done in the framework put forward by Siegel\\cite{WS} and by Floreanini and Jackiw\\cite{FJ} (FJ). We propose a field redefinition that discloses the presence of a noton, a non dynamical field, in Siegel's formulation for chiral bosons. The presence of a noton in the Siegel CBS is a new and surprising result, that separates dynamics from symmetry by diagonalising the Siegel action into the FJ and the noton action. While the first describes the chiral dynamics, the noton carries the symmetry contents, acquiring dynamics upon quantization and is fully responsible for the Siegel anomaly. The diagonal representation proposed here is used to study the effect of quantum interference between gauged rightons and leftons.

  10. Adaptive transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-01-01

    This paper studies the performance of adaptive transmit channel selection in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to- interference-plus- noise ratios (SINRs). Two interference cancelation algorithms, which are the dominant cancelation and the less complex arbitrary cancelation, are considered, for which the receive antenna array is assumed to have small angular spread. Analytical formulation for some performance measures in addition to several processing complexity and numerical comparisons between various adaptation schemes are presented. ©2010 IEEE.

  11. Many-body quantum interference on hypercubes

    Science.gov (United States)

    Dittel, Christoph; Keil, Robert; Weihs, Gregor

    2017-03-01

    Beyond the regime of distinguishable particles, many-body quantum interferences influence quantum transport in an intricate manner. However, symmetries of the single-particle transformation matrix alleviate this complexity and even allow the analytic formulation of suppression laws, which predict final states to occur with a vanishing probability due to total destructive interference. Here we investigate the symmetries of hypercube graphs and their generalisations with arbitrary identical subgraphs on all vertices. We find that initial many-particle states, which are invariant under self-inverse symmetries of the hypercube, lead to a large number of suppressed final states. The condition for suppression is determined solely by the initial symmetry, while the fraction of suppressed states is given by the number of independent symmetries of the initial state. Our findings reveal new insights into particle statistics for ensembles of indistinguishable bosons and fermions and may represent a first step towards many-particle quantum protocols in higher-dimensional structures.

  12. Intercell Interference Coordination through Limited Feedback

    Directory of Open Access Journals (Sweden)

    Lingjia Liu

    2010-01-01

    Full Text Available We consider the applications of multicell transmission schemes to the downlink of future wireless communication networks. A multicell multiple-input multiple output-(MIMOs based scheme with limited coordination among neighboring base stations (BSs is proposed to effectively combat the intercell interference by taking advantage of the degreesoffreedom in the spatial domain. In this scheme, mobile users are required to feedback channel-related information to both serving base station and interfering base station. Furthermore, a chordal distance-based compression scheme is introduced to reduce the feedback overhead. The performance of the proposed scheme is investigated through theoretical analysis as well as system level simulations. Both results suggest that the so-called “intercell interference coordination through limited feedback” scheme is a very good candidate for improving the cell-edge user throughput as well as the average cell throughput of the future wireless communication networks.

  13. Multiscale Investigation of Chemical Interference in Proteins

    CERN Document Server

    Samiotakis, Antonios; Cheung, Margaret S

    2010-01-01

    We developed a multiscale approach (MultiSCAAL) that integrates the potential of mean force (PMF) obtained from all-atomistic molecular dynamics simulations with a knowledge-based energy function for coarse-grained molecular simulations in better exploring the energy landscape of a small protein under chemical interference such as chemical denaturation. An excessive amount of water molecules in all-atomistic molecular dynamics simulations often negatively impacts the sampling efficiency of some advanced sampling techniques such as the replica exchange method and it makes the investigation of chemical interferences on protein dynamics difficult. Thus, there is a need to develop an effective strategy that focuses on sampling structural changes in protein conformations rather than solvent molecule fluctuations. In this work, we address this issue by devising a multiscale simulation scheme (MultiSCAAL) that bridges the gap between all-atomistic molecular dynamics simulation and coarse-grained molecular simulation...

  14. Index Coding - An Interference Alignment Perspective

    CERN Document Server

    Maleki, Hamed; Jafar, Syed A

    2012-01-01

    The index coding problem is studied from an interference alignment perspective, providing new results as well as new insights into, and generalizations of, previously known results. An equivalence is established between multiple unicast index coding where each message is desired by exactly one receiver, and multiple groupcast index coding where a message can be desired by multiple receivers, which settles the heretofore open question of insufficiency of linear codes for the multiple unicast index coding problem by equivalence with multiple groupcast settings where this question has previously been answered. Necessary and sufficient conditions for the achievability of rate half per message are shown to be a natural consequence of interference alignment constraints, and generalizations to feasibility of rate $\\frac{1}{L+1}$ per message when each destination desires at least $L$ messages, are similarly obtained. Finally, capacity optimal solutions are presented to a series of symmetric index coding problems insp...

  15. Belief Propagation Methods for Intercell Interference Coordination

    CERN Document Server

    Rangan, Sundeep

    2010-01-01

    We consider a broad class of interference coordination and resource allocation problems for wireless links where the goal is to maximize the sum of functions of individual link rates. Such problems arise in the context of, for example, fractional frequency reuse (FFR) for macro-cellular networks and dynamic interference management in femtocells. The resulting optimization problems are typically hard to solve optimally even using centralized algorithms but are an essential computational step in implementing rate-fair and queue stabilizing scheduling policies in wireless networks. We consider a belief propagation framework to solve such problems approximately. In particular, we construct approximations to the belief propagation iterations to obtain computationally simple and distributed algorithms with low communication overhead. Notably, our methods are very general and apply to, for example, the optimization of transmit powers, transmit beamforming vectors, and sub-band allocation to maximize the above object...

  16. Unruh effect and macroscopic quantum interference

    CERN Document Server

    Steane, Andrew

    2015-01-01

    We investigate the influence of Unruh radiation on matter-wave interferometry experiments using neutral objects modeled as dielectric spheres. The Unruh effect leads to a loss of coherence through momentum diffusion. This is a fundamental source of decoherence that affects all objects having electromagnetic interactions. However, the effect is not large enough to prevent the observation of interference for objects of any size, even when the path separation is larger than the size of the object. When the acceleration in the interferometer arms is large, inertial tidal forces will disrupt the material integrity of the interfering objects before the Unruh decoherence of the centre of mass motion is sufficient to prevent observable interference.

  17. Interference Rejection Techniques in DSSS Communication System

    Institute of Scientific and Technical Information of China (English)

    GONGXiangyang; HUGuangrui

    2003-01-01

    It is known that the narrowband interfer-ence rejection capability of a direct sequence (DS) spread spectrum (SS) system can be enhanced considerably by an interference rejection algorithm prior to correlating it with the pseudo noise (PN) sequence. For narrowband gaussian noise (NGN), the techniques in common use are transver-sal filter. It models SS signal and NGN as stationary, then utilizes temporal correlation difference between SS signal and NBL however, SS signal and NGN are cyclostation-ary (CS). CS signal has correlation in frequency domain called spectrum correlation, which can not be employed by transversal filter. In this article, SS signal and NBIare modeled as CS and FRESH filter is adopted to exploit the correlation both in time domain and frequency domain.Computer simulation shows that FRESH filter can improve the system performance considerably compared with con-ventional transversal filter.

  18. Heuristic explanation of quantum interference experiments

    CERN Document Server

    Guowen, W

    2005-01-01

    A particle is described as a non-spreading wave packet satisfying a linear equation within the framework of special relativity. Young's and other interference experiments are explained with a hypothesis that there is a coupling interaction between the peaked and non-peaked pieces of the wave packet. This explanation of the interference experiments provides a realistic interpretation of quantum mechanics. The interpretation implies that there is physical reality of particles and no wave function collapse. It also implies that neither classical mechanics nor current quantum mechanics is a complete theory for describing physical reality and the Bell inequalities are not the proper touchstones for reality and locality. The problems of the boundary between the macro-world and micro-world and the de-coherence in the transition region (meso-world) between the two are discussed. The present interpretation of quantum mechanics is consistent with the physical aspects of the Copenhagen interpretation, such as, the super...

  19. Interference Alignment with Analog Channel State Feedback

    CERN Document Server

    Ayach, Omar El

    2010-01-01

    Interference alignment (IA) is a multiplexing gain optimal transmission strategy for the interference channel with an arbitrary number of users. While the achieved sum rate with IA is much higher than previously thought possible, the improvement comes at the cost of requiring network channel state information at the transmitters. This can be achieved by explicit feedback, a flexible yet costly approach that incurs large overhead and limits throughput. We propose using analog feedback as an alternative to limited feedback or reciprocity based alignment. We show that the full multiplexing gain observed with perfect channel knowledge is preserved by analog feedback and the mean loss in sum rate is bounded by a constant when signal-to-noise ratio is comparable in both forward and feedback channels. When such feedback quality is not quite possible, a fraction of the degrees of freedom is achieved. We consider the overhead of training and feedback and use this framework to optimize the system's effective throughput...

  20. Canceling Interference in Acupuncture Points Signal

    Directory of Open Access Journals (Sweden)

    Yanexy San Martín Reyes

    2012-07-01

    Full Text Available The present paper propose the cancellation of interference or artifacts by the method of Allen in signals captured in different acupuncture points (Small Intestine Meridian, points ID1-ID2 and ID1-ID19. It is considered that the biosignal under study should be able to be characterized after its acquisition by subtracting the different interference variables that may coexist in the measurement zone, as it is in the case of ECG or any other artifact. The biosignal obtained as a result of the cancellation will be the acupuncture signal or from its imperfection another wave can be obtained as from a bioelectrical point of view such imperfection can be characterized and at the same time can bb useful to establish a long-term correspondence between the behavior of the signals on various acupuncture points and different diseases.

  1. Interference comb-spectroscopy with increasing sensitivity

    Science.gov (United States)

    Pulkin, Sergey; Borisov, Evgenii; Balabas, Michail; Uvarova, Svetlana; Shevtzov, Vladimir; Kalinichev, Alexei; Shoev, Vladislav; Venediktov, Dmitrii; Venediktov, Vladimir

    2016-10-01

    The paper considers the use of holographic interferometer for hologram recording of the wide spectrum from the comb - generator of the femtosecond laser was applied for illuminating of Michelson interferometer with atomic vapor. The behavior of spectral interference fringes on the exit slit of spectrograph reflects the behavior of nonlinear refractive index. The method of holographic interferometry with increasing sensitivity using phase modulator was applied for digital hologram processing.

  2. rf superconducting quantum interference device metamaterials

    Science.gov (United States)

    Lazarides, N.; Tsironis, G. P.

    2007-04-01

    A rf superconducting quantum interference device (SQUID) array in an alternating magnetic field is investigated with respect to its effective magnetic permeability, within the effective medium approximation. This system acts as an inherently nonlinear magnetic metamaterial, leading to negative magnetic response, and thus negative permeability above the resonance frequency of the individual SQUIDs. Moreover, the permeability exhibits oscillatory behavior at low field intensities, allowing its tuning by a slight change of the intensity of the applied field.

  3. Development of Studies on RNA Interference

    Institute of Scientific and Technical Information of China (English)

    Li ZHANG; Yaqiong ZHANG; Lina SHE; Wenting XU; Yangying JIA; Shiqing XIE; WenliSUN; Quan LIANG

    2012-01-01

    RNA interference (RNAi), caused by endogenous or exogenous double- stranded RNA (dsRNA) homologous with target genes, refers to gene silencing widely existing in animals and plants. It was first found in plants, and now it has developed into a kind of biotechnology as well as an important approach in post- genome era. This paper is to summarize the achievements of studies on RNAi tech- nology in basic biology, medicine, pharmacy, botany and other fields.

  4. CRISPR interference directs strand specific spacer acquisition.

    Directory of Open Access Journals (Sweden)

    Daan C Swarts

    Full Text Available BACKGROUND: CRISPR/Cas is a widespread adaptive immune system in prokaryotes. This system integrates short stretches of DNA derived from invading nucleic acids into genomic CRISPR loci, which function as memory of previously encountered invaders. In Escherichia coli, transcripts of these loci are cleaved into small RNAs and utilized by the Cascade complex to bind invader DNA, which is then likely degraded by Cas3 during CRISPR interference. RESULTS: We describe how a CRISPR-activated E. coli K12 is cured from a high copy number plasmid under non-selective conditions in a CRISPR-mediated way. Cured clones integrated at least one up to five anti-plasmid spacers in genomic CRISPR loci. New spacers are integrated directly downstream of the leader sequence. The spacers are non-randomly selected to target protospacers with an AAG protospacer adjacent motif, which is located directly upstream of the protospacer. A co-occurrence of PAM deviations and CRISPR repeat mutations was observed, indicating that one nucleotide from the PAM is incorporated as the last nucleotide of the repeat during integration of a new spacer. When multiple spacers were integrated in a single clone, all spacer targeted the same strand of the plasmid, implying that CRISPR interference caused by the first integrated spacer directs subsequent spacer acquisition events in a strand specific manner. CONCLUSIONS: The E. coli Type I-E CRISPR/Cas system provides resistance against bacteriophage infection, but also enables removal of residing plasmids. We established that there is a positive feedback loop between active spacers in a cluster--in our case the first acquired spacer--and spacers acquired thereafter, possibly through the use of specific DNA degradation products of the CRISPR interference machinery by the CRISPR adaptation machinery. This loop enables a rapid expansion of the spacer repertoire against an actively present DNA element that is already targeted, amplifying the

  5. Robust Satellite Communications Under Hostile Interference

    Science.gov (United States)

    2016-05-20

    extremely hardened radios that sacrifice communications performance for more advanced jamming protection. To provide an escape from this trend, we...being targeted, the common three being: communications , radar, and radio navigation (e.g., Global Positioning System (GPS) and Global Navigation...AFRL-RV-PS- AFRL-RV-PS- TR-2016-0079 TR-2016-0079 ROBUST SATELLITE COMMUNICATIONS UNDER HOSTILE INTERFERENCE Marc Lichtman and Jeffrey Reed

  6. Research Progress on Multimode Interference Switches

    Institute of Scientific and Technical Information of China (English)

    GAO Qing; SHENG Zhi-rui; JIANG Xiao-qing; WANG Ming-hua

    2005-01-01

    Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical switches, the multimode interference(MMI) switches have received considerable attention due to their unique merits. The structures and operation principles of various types of MMI switches are introduced,and the recent progresses of MMI switches are also discussed.

  7. Interference to satellite systems produced by rainscatter

    Science.gov (United States)

    Howell, R. G.; Thompson, P. T.

    1991-10-01

    Data, obtained from eight small dish receivers, placed around the United Kingdom, and designed to detect the scattering by rain of signals from the British Telecom (BT) 11 GHz microwave network, is presented. Fifteen site years of measurements were analyzed to produce cumulative distributions of effective receive antenna noise temperature and, where rainscattered signals were detected, cumulative distributions of transmission loss. The results obtained are compared with those predicted by a BT/University of Essex rainscatter interference prediction model (SCIMP).

  8. Control and signal processing by transcriptional interference

    OpenAIRE

    2009-01-01

    A transcriptional activator can suppress gene expression by interfering with transcription initiated by another activator. Transcriptional interference has been increasingly recognized as a regulatory mechanism of gene expression. The signals received by the two antagonistically acting activators are combined by the polymerase trafficking along the DNA. We have designed a dual-control genetic system in yeast to explore this antagonism systematically. Antagonism by an upstream activator bears ...

  9. In Vivo Imaging of RNA Interference

    OpenAIRE

    Hong, Hao; Zhang,Yin; Cai, Weibo

    2010-01-01

    RNA interference (RNAi), an effective technique for regulating/silencing specific genes, can be applied to treat various diseases. Multiple clinical trials using RNAi are ongoing and molecular imaging can serve as a powerful tool in RNAi-based therapies. This brief review will highlight the current progress on in vivo imaging of RNAi delivery and silencing effects. Incorporation of suitable molecular imaging techniques into future RNAi-based clinical trials will provide more pieces of the puz...

  10. Interference Phenomena in Medium Induced Radiation

    CERN Document Server

    Casalderrey-Solana, Jorge

    2011-01-01

    We consider the interference pattern for the medium-induced gluon radiation produced by a color singlet quark-antiquark antenna embedded in a QCD medium with size $L$ and `jet quenching' parameter $\\hat q$. Within the BDMPS-Z regime, we demonstrate that, for a dipole opening angle $\\theta_{q\\bar q} \\gg\\theta_c\\equiv {2}/{\\sqrt{\\hat q L^3}}$, the interference between the medium--induced gluon emissions by the quark and the antiquark is suppressed with respect to the direct emissions. This is so since direct emissions are delocalized throughout the medium and thus yield contributions proportional to $L$ while interference occurs only between emissions at early times, when both sources remain coherent. Thus, for $\\tqq \\gg\\theta_c$, the medium-induced radiation is the sum of the two spectra individually produced by the quark and the antiquark, without coherence effects like angular ordering. For $\\tqq \\ll\\theta_c$, the medium--induced radiation vanishes.

  11. Immunizing digital systems against electromagnetic interference

    Science.gov (United States)

    Ewing, P. D.; Korsah, K.; Antonescu, C.

    This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Secondly, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced.

  12. Eliminating ultrasonic interference from respiratory muscle EMG.

    Science.gov (United States)

    Platt, R S; Kieser, T M; Easton, P A

    1998-05-01

    Fine wire recordings of the respiratory muscle electromyogram are often employed to represent muscle activity, and recently ultrasound-sonomicrometry has become a common method of measuring length of respiratory muscles in both acute and chronic preparations. Although recording both EMG and sonomicrometry simultaneously has become standard practice, there has not been any consideration of the potential confounding influence of ultrasound noise upon the recorded EMG spectrum. Activation of the sonomicrometry-ultrasound tranducer introduces a high frequency, high amplitude voltage pulse plus harmonics, which can contaminate the EMG spectrum directly, as well as through aliasing when EMG is sampled directly digitally. We describe the use of a new, combined, wing stabilized sonomicrometry- and EMG measurement transducer to characterize exactly the influence of ultrasound upon the crural diaphragm EMG spectrum, and the development of digital filtering techniques which effectively eliminate the ultrasound interference. Two alternative methods of avoiding ultrasound-EMG interference are also considered. The isolation and elimination of ultrasound-sonomicrometry signal interference may be important in studies where EMG and length are measured together.

  13. Control and signal processing by transcriptional interference

    Science.gov (United States)

    Buetti-Dinh, Antoine; Ungricht, Rosemarie; Kelemen, János Z; Shetty, Chetak; Ratna, Prasuna; Becskei, Attila

    2009-01-01

    A transcriptional activator can suppress gene expression by interfering with transcription initiated by another activator. Transcriptional interference has been increasingly recognized as a regulatory mechanism of gene expression. The signals received by the two antagonistically acting activators are combined by the polymerase trafficking along the DNA. We have designed a dual-control genetic system in yeast to explore this antagonism systematically. Antagonism by an upstream activator bears the hallmarks of competitive inhibition, whereas a downstream activator inhibits gene expression non-competitively. When gene expression is induced weakly, the antagonistic activator can have a positive effect and can even trigger paradoxical activation. Equilibrium and non-equilibrium models of transcription shed light on the mechanism by which interference converts signals, and reveals that self-antagonism of activators imitates the behavior of feed-forward loops. Indeed, a synthetic circuit generates a bell-shaped response, so that the induction of expression is limited to a narrow range of the input signal. The identification of conserved regulatory principles of interference will help to predict the transcriptional response of genes in their genomic context. PMID:19690569

  14. Interference suppression in noise radar systems

    Science.gov (United States)

    Djukanović, Slobodan; Daković, Miloš; Thayaparan, Thayananthan; Stanković, Ljubiša

    2011-06-01

    This paper addresses the issue of interference suppression in noise radars. The proposed methods can be divided into non-parametric and parametric ones. The considered non-parametric methods are based on linear time-frequency (TF) tools, namely the short-time Fourier transform (STFT) and local polynomial Fourier transform (LPFT). The STFT is the simplest TF method, but, due to the resolution problem, it performs poorly with highly nonstationary interferences. The LPFT resolves the resolution problem, however at the cost of increased complexity. In parametric methods, the phase of interference is locally approximated by a polynomial, which is motivated by the Weierstrass's theorem. Using the phase approximation, the corrupted received signal is demodulated and successively filtered. Two methods for polynomial phase approximation are considered, the high-order ambiguity function (HAF) and product high-order ambiguity function (PHAF). The method based on the HAF is computationally efficient; however, it suffers from the identifiability problem when multicomponent signals are considered. The identifiability problem can be resolved using the PHAF.

  15. 47 CFR 27.64 - Protection from interference.

    Science.gov (United States)

    2010-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.64 Protection from interference. Wireless Communications Service (WCS) stations operating in full accordance with applicable FCC rules and... provided against interference caused by tropospheric and ionospheric propagation of signals....

  16. Atmospheric composition change: Ecosystems-Atmosphere interactions

    NARCIS (Netherlands)

    Fowler, D.; Pilegaard, K.; Sutton, M.A.; Ambus, P.; Raivonen, M.; Duyzer, J.; Simpson, D.; Fagerli, H.; Fuzzi, S.; Schjoerring, J.K.; Granier, C.; Neftel, A.; Isaksen, I.S.A.; Laj, P.; Maione, M.; Monks, P.S.; Burkhardt, J.; Daemmgen, U.; Neirynck, J.; Personne, E.; Wichink Kruit, R.J.; Butterbach-Bahl, K.; Flechard, C.; Tuovinen, J.P.; Coyle, M.; Gerosa, G.; Loubet, B.; Altimir, N.; Gruenhage, L.; Ammann, C.; Cieslik, S.; Paoletti, E.; Mikkelsen, T.N.; Ro-Poulsen, H.; Cellier, P.; Cape, J.N.; Horvath, L.; Loreto, F.; Niinemets, U.; Palmer, P.I.; Rinne, J.; Misztal, P.; Nemitz, E.; Nilsson, D.; Pryor, S.; Gallagher, M.W.; Vesala, T.; Skiba, U.; Brueggemann, N.; Zechmeister-Boltenstern, S.; Williams, J.; O'Dowd, C.; Facchini, M.C.; Leeuw, de G.; Flossman, A.; Chaumerliac, N.; Erisman, J.W.

    2009-01-01

    Ecosystems and the atmosphere: This review describes the state of understanding the processes involved in the exchange of trace gases and aerosols between the earth's surface and the atmosphere. The gases covered include NO, NO2, HONO, HNO3, NH3, SO2, DMS, Biogenic VOC, O-3, CH4, N2O and particles i

  17. Quantum Interference of Multiple Beams Induced by Multiple Scattering

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Mortensen, N. Asger; Lodahl, Peter

    2011-01-01

    We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging.......We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging....

  18. Capacity Regions and Sum-Rate Capacities of Vector Gaussian Interference Channels

    CERN Document Server

    Shang, Xiaohu; Kramer, Gerhard; Poor, H Vincent

    2009-01-01

    The capacity regions of vector, or multiple-input multiple-output, Gaussian interference channels are established for very strong interference and aligned strong interference. Furthermore, the sum-rate capacities are established for Z interference, noisy interference, and mixed (aligned weak/intermediate and aligned strong) interference. These results generalize known results for scalar Gaussian interference channels.

  19. Visualizing the Solute Vaporization Interference in Flame Atomic Absorption Spectroscopy

    Science.gov (United States)

    Dockery, Christopher R.; Blew, Michael J.; Goode, Scott R.

    2008-01-01

    Every day, tens of thousands of chemists use analytical atomic spectroscopy in their work, often without knowledge of possible interferences. We present a unique approach to study these interferences by using modern response surface methods to visualize an interference in which aluminum depresses the calcium atomic absorption signal. Calcium…

  20. Bimanual Interference Associated with Handling Different Tool Transformations

    Science.gov (United States)

    Massen, Cristina; Sattler, Christine

    2013-01-01

    Research on bimanual coordination of hand movements has identified several loci of bimanual interference, including interference because of programming different movement parameters or selecting different targets for the two hands. This study investigates the extent and origin of interference when participants execute bimanual actions with tools.…

  1. Addressing Cultural and Native Language Interference in Second Language Acquisition

    Science.gov (United States)

    Allard, Daniele; Bourdeau, Jacqueline; Mizoguchi, Riichiro

    2011-01-01

    This paper addresses the problem of cultural and native language interference in second/foreign language acquisition. More specifically, it examines issues of interference that can be traced to a student's native language and that also have a cultural component. To this effect, an understanding of what actually comprises both interference and…

  2. Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2008-11-01

    Full Text Available In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer for the detection of nitrous acid (HONO in the atmosphere (DL 0.2 pptV was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data.

  3. Mirador - Atmospheric Composition

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Atmospheric Composition is focused on the composition of Earth's atmosphere in relation to climate prediction, solar effects,...

  4. Planetary Atmospheric Electricity

    CERN Document Server

    Leblanc, F; Yair, Y; Harrison, R. G; Lebreton, J. P; Blanc, M

    2008-01-01

    This volume presents our contemporary understanding of atmospheric electricity at Earth and in other solar system atmospheres. It is written by experts in terrestrial atmospheric electricity and planetary scientists. Many of the key issues related to planetary atmospheric electricity are discussed. The physics presented in this book includes ionisation processes in planetary atmospheres, charge generation and separation, and a discussion of electromagnetic signatures of atmospheric discharges. The measurement of thunderstorms and lightning, including its effects and hazards, is highlighted by articles on ground and space based instrumentation, and new missions.Theory and modelling of planetary atmospheric electricity complete this review of the research that is undertaken in this exciting field of space science. This book is an essential research tool for space scientists and geoscientists interested in electrical effects in atmospheres and planetary systems. Graduate students and researchers who are new to t...

  5. Our shared atmosphere

    Science.gov (United States)

    Our atmosphere is a precious and fascinating resource, providing air to breath, shielding us from harmful ultraviolet radiation (UV), and maintaining a comfortable climate. Since the industrial revolution, people have significantly altered the composition of the atmosphere throu...

  6. From atmospheric awareness to active materiality

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2013-01-01

    surroundings, where the environmental qualities are implicit and conditions and phenomena are bound together in a reciprocal dependence. Therefore, material is neither seen as an isolated element, nor as mere substance expressing tectonic character. Transcending its generative potential and focusing on its...... of continuous and complex interferences revealed through our perception. Therefore, to design considering an atmospheric approach means to focus on how the space is going to appear, to be experienced or to be felt. What immediately follows this assumption is, then, the exploration of works and design processes...... with an attempt to trace associations and draw out design protocols, focusing on ways in which atmosphere can be consciously generated or manipulated. The aim is thus to examine ‘the atmospheric’ as a spatial quality, an experiential property as well as a sensory background and materiality as one...

  7. Atmospheric and accelerator neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoichiro [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo Higashi-Mozumi, Kamioka, Hida-City, Gifu 506-1205 (Japan)

    2006-05-15

    Results from the atmospheric neutrino measurements are presented. Evidence for the {nu}{sub {tau}} appearance in the atmospheric neutrino events was shown by statistical methods. The long baseline oscillation experiment using man-made neutrinos has confirmed the atmospheric neutrino oscillation. The future accelerator experiments are briefly discussed.

  8. Atmospheric refraction : a history

    NARCIS (Netherlands)

    Lehn, WH; van der Werf, S

    2005-01-01

    We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of un

  9. Improved Interference configuration for structured illumination microscopy

    Science.gov (United States)

    Chen, Houkai; Wei, Shibiao; Wu, Xiaojing; Yang, Yong; Zhang, Yuquan; Du, Luping; Liu, Jun; Zhu, Siwei; Yuan, Xiaocong

    2017-02-01

    We present an improved structured illumination configuration for structured illumination microscopy (SIM) based on spatial light modulator. Precise phase shifts and rotation of illumination fringes can be dynamically controlled using a spatial light modulator. The method is different from the conventional illumination configuration that are based on interference of ±1 diffractive order light. The experimental setup requires less optical elements making it compact, reliable, and suitable for integration. The method has been applied in the standing-wave total internal reflection fluorescent microscopy. High lateral resolution of sub-100 nm was achieved in single directional resolution enhancement experiments.

  10. Transient interference of transmission and incidence

    CERN Document Server

    Pérez-Prieto, A L; Muga, J G

    2000-01-01

    Due to a transient quantum interference during a wavepacket collision with a potential barrier, a particular momentum, that depends on the potential parameters but is close to the initial average momentum, becomes suppressed. The hole left pushes the momentum distribution outwards leading to a significant constructive enhancement of lower and higher momenta. This is explained in the momentum complex-plane language in terms of a saddle point and two contiguous ``structural'' poles, which are not associated with resonances but with incident and transmitted components of the wavefunction.

  11. Quantum Radiation Reaction: From Interference to Incoherence.

    Science.gov (United States)

    Dinu, Victor; Harvey, Chris; Ilderton, Anton; Marklund, Mattias; Torgrimsson, Greger

    2016-01-29

    We investigate quantum radiation reaction in laser-electron interactions across different energy and intensity regimes. Using a fully quantum approach which also accounts exactly for the effect of the strong laser pulse on the electron motion, we identify in particular a regime in which radiation reaction is dominated by quantum interference. We find signatures of quantum radiation reaction in the electron spectra which have no classical analogue and which cannot be captured by the incoherent approximations typically used in the high-intensity regime. These signatures are measurable with presently available laser and accelerator technology.

  12. Quantum radiation reaction: from interference to incoherence

    CERN Document Server

    Dinu, Victor; Ilderton, Anton; Marklund, Mattias; Torgrimsson, Greger

    2015-01-01

    We investigate quantum radiation reaction in laser-electron interactions across different energy and intensity regimes. Using a fully quantum approach which also accounts exactly for the effect of the strong laser pulse on the electron motion, we identify in particular a regime in which radiation reaction is dominated by quantum interference. We find signatures of quantum radiation reaction in the electron spectra which have no classical analogue and which cannot be captured by the incoherent approximations typically used in the high-intensity regime. These signatures are measurable with presently available laser and accelerator technology.

  13. RNA interference and its application in plants

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    RNA interference (RNAi), a process that inhibits gene expression by the double-stranded RNA (dsRNA), causes the deg-radation of target messenger RNA molecules. RNAi exists in almost all organisms. We review the recent history of RNAi studies,RNAi molecular mechanisms, characteristics and RNAi applications in higher plants. At the same time, the prospect of RNAi appli-cations in functional genomics and genetic improvement of higher plants and possible future problems and possibilities are also dis-cussed.

  14. Interference Tests at Kawerau, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Burnell, John G.; McGuinness, Mark J.

    1987-01-20

    Analysis of interference tests at the Kawerau geothermal field in New Zealand has indicated that the reservoir may be viewed on a coarse scale as a two-layer structure. While these layers have high permeabilities, they are in poor hydrological communication with each other. The shallower layer is modelled as a finite cylindrical reservoir. The deeper layer is modelled as a larger cylindrical reservoir with recharge from the sides. The fitted permeabilities and storativities suggest the importance of flow in fractures at Kawerau. 2 tabs., 14 figs., 8 refs.

  15. Stroop interference in adults with dyslexia.

    Science.gov (United States)

    Proulx, Michael J; Elmasry, Hannah-May

    2015-01-01

    Prior research on developmental dyslexia using Stroop tasks with young participants has found increased interference in participants with dyslexia relative to controls. Here we extend these findings to adult participants, and introduce a novel test of Stroop incongruity, whereby the color names appeared on an object colored in the incongruent color. The results imply that impaired inhibitory and executive attentional mechanisms are still deficient in adults with dyslexia and that other forms of attentional mechanisms, such as object-based attention, might also be impaired in dyslexia. Dyslexia arises not only from deficits in phonological processing, but from attentional mechanisms as well.

  16. Angular momentum sensitive two-center interference.

    Science.gov (United States)

    Ilchen, M; Glaser, L; Scholz, F; Walter, P; Deinert, S; Rothkirch, A; Seltmann, J; Viefhaus, J; Decleva, P; Langer, B; Knie, A; Ehresmann, A; Al-Dossary, O M; Braune, M; Hartmann, G; Meissner, A; Tribedi, L C; AlKhaldi, M; Becker, U

    2014-01-17

    In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

  17. Preserved cumulative semantic interference despite amnesia

    Directory of Open Access Journals (Sweden)

    Gary Michael Oppenheim

    2015-05-01

    As predicted by Oppenheim et al’s (2010 implicit incremental learning account, WRP’s BCN RTs demonstrated strong (and significant repetition priming and semantic blocking effects (Figure 1. Similar to typical results from neurally intact undergraduates, WRP took longer to name pictures presented in semantically homogeneous blocks than in heterogeneous blocks, an effect that increased with each cycle. This result challenges accounts that ascribe cumulative semantic interference in this task to explicit memory mechanisms, instead suggesting that the effect has the sort of implicit learning bases that are typically spared in hippocampal amnesia.

  18. Interference Alignment in Dense Wireless Networks

    CERN Document Server

    Niesen, Urs

    2009-01-01

    We consider arbitrary dense wireless networks, in which $n$ nodes are placed in an arbitrary (deterministic) manner on a square region of unit area and communicate with each other over Gaussian fading channels. We provide inner and outer bounds for the $n\\times n$-dimensional unicast and the $n\\times 2^n$-dimensional multicast capacity regions of such a wireless network. These inner and outer bounds differ only by a factor $O(\\log(n))$, yielding a fairly tight scaling characterization of the entire regions. The communication schemes achieving the inner bounds use interference alignment as a central technique and are surprisingly simple.

  19. Radio Frequency Interference Mitigation at the WSRT

    CERN Document Server

    Fridman, P A; Millenaar, R P

    2010-01-01

    The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is proposed here for the Westerbork Synthesis Radio Telescope based on a powerful field programmable gate array processor. In this system the radio astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine back-end correlation processing takes place. The high temporal and frequency resolution of RFIMS allows the detection and excision of RFI better than do standard radio telescope back-end configurations.

  20. Angular Momentum Sensitive Two-Center Interference

    Science.gov (United States)

    Ilchen, M.; Glaser, L.; Scholz, F.; Walter, P.; Deinert, S.; Rothkirch, A.; Seltmann, J.; Viefhaus, J.; Decleva, P.; Langer, B.; Knie, A.; Ehresmann, A.; Al-Dossary, O. M.; Braune, M.; Hartmann, G.; Meissner, A.; Tribedi, L. C.; AlKhaldi, M.; Becker, U.

    2014-01-01

    In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

  1. Multipolar interference for directed light emission.

    Science.gov (United States)

    Hancu, Ion M; Curto, Alberto G; Castro-López, Marta; Kuttge, Martin; van Hulst, Niek F

    2014-01-08

    By directing light, optical antennas can enhance light-matter interaction and improve the efficiency of nanophotonic devices. Here we exploit the interference among the electric dipole, quadrupole, and magnetic dipole moments of a split-ring resonator to experimentally realize a compact directional optical antenna. This single-element antenna design robustly directs emission even when covered with nanometric emitters at random positions, outperforming previously demonstrated nanoantennas with a bandwidth of 200 nm and a directivity of 10.1 dB from a subwavelength structure. The advantages of this approach bring directional optical antennas closer to practical applications.

  2. Review Results on Wing-Body Interference

    OpenAIRE

    Frolov Vladimir

    2016-01-01

    The paper presents an overview of results for wing-body interference, obtained by the author for varied wing-body combinations. The lift-curve slopes of the wing-body combinations are considered. In this paper a discrete vortices method (DVM) and 2D potential model for cross-flow around fuselage are used. The circular and elliptical cross-sections of the fuselage and flat wings of various forms are considered. Calculations showed that the value of the lift-curve slopes of the wing-body combin...

  3. Strong Correlation of Fluorescence Photons without Quantum Interference

    Institute of Scientific and Technical Information of China (English)

    HU Xiang-Ming; WANG Fei

    2007-01-01

    It has been predicted that a driven three-level V atom can emit strongly correlated fluorescence photons in the presence of quantum interference. Here we examine the effects of quantum interference on the intensity correlation of fluorescence photons emitted from a driven three-level A atom. Unexpectedly, strong correlation occurs without quantum interference. The quantum interference tends to reduce the correlation function to a normal level. The essential difference between these two cases is traced to the different effects of quantum interference on coherent population trapping (CPT). For the V atom, quantum interference and coherent excitation combine to lead to CPT. For the A atom, however, the quantum interference tends to spoil CPT while the coherent excitation induces the effect.

  4. Italian, French, Polish: in the Bermuda Triangle of linguistic interference

    Directory of Open Access Journals (Sweden)

    Małgorzata Balicka

    2009-01-01

    Full Text Available Increasing contacts between nations make people learn foreign languages. Unfortunately, the use of more than one language system may cause errors due to linguistic interference. In the present paper we consider different definitions of this phenomenon and describe the conditions reąuired for its presence, along with proposals on how to eliminate interference mistakes. A specific case is false friends, words similar in form but different in meaning, which can lead to misunderstandings or even disgrace. As interference implies the knowledge of at least two languages, bilingualism is another problem discussed in the paper. We present different approaches to interference and study the relation between bilingualism and interference. Finally, we discuss loanwords as one of the results of interference. With all these considerations in mind we can make a specific study of interference mistakes made by Polish students of Italian philology.

  5. Auditory list memory and interference processes in monkeys.

    Science.gov (United States)

    Wright, A A

    1999-07-01

    Memory of 2 rhesus monkeys (Macaca mulatta) was tested in a serial probe recognition task with lists of 4 natural or environmental sounds, different retention intervals, and different manipulations of interference. At short retention intervals, increasing the separation of list items reduced the primacy effect and produced a recency effect. Similar results were shown by increasing interference across lists through item repetitions or making the first 2 list items high-interference items. These results indicated that decreasing first-item performance reduced proactive interference on memory of the last list items. At long (20 s) retention intervals, making the last list items of high interference reduced the recency effect, reduced retroactive interference, and produced a primacy effect. Taken together, interference plays a role in determining the primacy and recency effects of the serial-position function.

  6. Reliability Estimations of Control Systems Effected by Several Interference Sources

    Institute of Scientific and Technical Information of China (English)

    Deng Bei-xing; Jiang Ming-hu; Li Xing

    2003-01-01

    In order to estab lish the sufficient and necessary condition that arbitrarily reliable systems can not be construc-ted with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of in-terference sources are raised respectively: interference source possessing real input vectors and constant reliable interference source. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbi-trarily reliable systems can not be constructed with the ele-ments effected by above interference sources.

  7. Aligned Interference Neutralization and the Degrees of Freedom of the 2x2x2 Interference Channel

    CERN Document Server

    Gou, Tiangao; Jeon, Sang-Woon; Chung, Sae-Young

    2010-01-01

    We show that the 2x2x2 interference channel, i.e., the multihop interference channel formed by concatenation of two 2-user interference channels achieves the min-cut outer bound value of 2 DoF, for almost all values of channel coefficients, for both time-varying or fixed channel coefficients. The key to this result is a new idea, called aligned interference neutralization, that provides a way to align interference terms over each hop in a manner that allows them to be cancelled over the air at the last hop.

  8. Atmospheric Habitable Zones in Y Dwarf Atmospheres

    Science.gov (United States)

    Yates, Jack S.; Palmer, Paul I.; Biller, Beth; Cockell, Charles S.

    2017-02-01

    We use a simple organism lifecycle model to explore the viability of an atmospheric habitable zone (AHZ), with temperatures that could support Earth-centric life, which sits above an environment that does not support life. To illustrate our model, we use a cool Y dwarf atmosphere, such as WISE J085510.83–0714442.5, whose 4.5–5.2 μm spectrum shows absorption features consistent with water vapor and clouds. We allow organisms to adapt to their atmospheric environment (described by temperature, convection, and gravity) by adopting different growth strategies that maximize their chance of survival and proliferation. We assume a constant upward vertical velocity through the AHZ. We found that the organism growth strategy is most sensitive to the magnitude of the atmospheric convection. Stronger convection supports the evolution of more massive organisms. For a purely radiative environment, we find that evolved organisms have a mass that is an order of magnitude smaller than terrestrial microbes, thereby defining a dynamical constraint on the dimensions of life that an AHZ can support. Based on a previously defined statistical approach, we infer that there are of the order of 109 cool Y brown dwarfs in the Milky Way, and likely a few tens of these objects are within 10 pc from Earth. Our work also has implications for exploring life in the atmospheres of temperate gas giants. Consideration of the habitable volumes in planetary atmospheres significantly increases the volume of habitable space in the galaxy.

  9. Relay self interference minimisation using tapped filter

    KAUST Repository

    Jazzar, Saleh

    2013-05-01

    In this paper we introduce a self interference (SI) estimation and minimisation technique for amplify and forward relays. Relays are used to help forward signals between a transmitter and a receiver. This helps increase the signal coverage and reduce the required transmitted signal power. One problem that faces relays communications is the leaked signal from the relay\\'s output to its input. This will cause an SI problem where the new received signal at the relay\\'s input will be added with the unwanted leaked signal from the relay\\'s output. A Solution is proposed in this paper to estimate and minimise this SI which is based upon using a tapped filter at the destination. To get the optimum weights for this tapped filter, some channel parameters must be estimated first. This is performed blindly at the destination without the need of any training. This channel parameter estimation method is named the blind-self-interference-channel-estimation (BSICE) method. The next step in the proposed solution is to estimate the tapped filter\\'s weights. This is performed by minimising the mean squared error (MSE) at the destination. This proposed method is named the MSE-Optimum Weight (MSE-OW) method. Simulation results are provided in this paper to verify the performance of BSICE and MSE-OW methods. © 2013 IEEE.

  10. Discrete interference modeling via boolean algebra.

    Science.gov (United States)

    Beckhoff, Gerhard

    2011-01-01

    Two types of boolean functions are considered, the locus function of n variables, and the interval function of ν = n - 1 variables. A 1-1 mapping is given that takes elements (cells) of the interval function to antidual pairs of elements in the locus function, and vice versa. A set of ν binary codewords representing the intervals are defined and used to generate the codewords of all genomic regions. Next a diallelic three-point system is reviewed in the light of boolean functions, which leads to redefining complete interference by a logic function. Together with the upper bound of noninterference already defined by a boolean function, it confines the region of interference. Extensions of these two functions to any finite number of ν are straightforward, but have been also made in terms of variables taken from the inclusion-exclusion principle (expressing "at least" and "exactly equal to" a decimal integer). Two coefficients of coincidence for systems with more than three loci are defined and discussed, one using the average of several individual coefficients and the other taking as coefficient a real number between zero and one. Finally, by way of a malfunction of the mod-2 addition, it is shown that a four-point system may produce two different functions, one of which exhibiting loss of a class of odd recombinants.

  11. Normalized GNSS Interference Pattern Technique for Altimetry

    Directory of Open Access Journals (Sweden)

    Miguel Angel Ribot

    2014-06-01

    Full Text Available It is well known that reflected signals from Global Navigation Satellite Systems (GNSS can be used for altimetry applications, such as monitoring of water levels and determining snow height. Due to the interference of these reflected signals and the motion of satellites in space, the signal-to-noise ratio (SNR measured at the receiver slowly oscillates. The oscillation rate is proportional to the change in the propagation path difference between the direct and reflected signals, which depends on the satellite elevation angle. Assuming a known receiver position, it is possible to compute the distance between the antenna and the surface of reflection from the measured oscillation rate. This technique is usually known as the interference pattern technique (IPT. In this paper, we propose to normalize the measurements in order to derive an alternative model of the SNR variations. From this model, we define a maximum likelihood estimate of the antenna height that reduces the estimation time to a fraction of one period of the SNR variation. We also derive the Cramér–Rao lower bound for the IPT and use it to assess the sensitivity of different parameters to the estimation of the antenna height. Finally, we propose an experimental framework, and we use it to assess our approach with real GPS L1 C/A signals.

  12. Quantum interference in an interfacial superconductor

    Science.gov (United States)

    Goswami, Srijit; Mulazimoglu, Emre; Monteiro, Ana M. R. V. L.; Wölbing, Roman; Koelle, Dieter; Kleiner, Reinhold; Blanter, Ya. M.; Vandersypen, Lieven M. K.; Caviglia, Andrea D.

    2016-10-01

    The two-dimensional superconductor that forms at the interface between the complex oxides lanthanum aluminate (LAO) and strontium titanate (STO) has several intriguing properties that set it apart from conventional superconductors. Most notably, an electric field can be used to tune its critical temperature (Tc; ref. 7), revealing a dome-shaped phase diagram reminiscent of high-Tc superconductors. So far, experiments with oxide interfaces have measured quantities that probe only the magnitude of the superconducting order parameter and are not sensitive to its phase. Here, we perform phase-sensitive measurements by realizing the first superconducting quantum interference devices (SQUIDs) at the LAO/STO interface. Furthermore, we develop a new paradigm for the creation of superconducting circuit elements, where local gates enable the in situ creation and control of Josephson junctions. These gate-defined SQUIDs are unique in that the entire device is made from a single superconductor with purely electrostatic interfaces between the superconducting reservoir and the weak link. We complement our experiments with numerical simulations and show that the low superfluid density of this interfacial superconductor results in a large, gate-controllable kinetic inductance of the SQUID. Our observation of robust quantum interference opens up a new pathway to understanding the nature of superconductivity at oxide interfaces.

  13. Interference Alignment: A one-sided approach

    CERN Document Server

    Ghauch, Hadi G

    2011-01-01

    Interference Alignment (IA) is the process of designing signals in such a way that they cast overlapping shadows at their unintended receivers, while remaining distinguishable at the intended ones. Our goal in this paper is to come up with an algorithm for IA that runs at the transmitters only (and is transparent to the receivers), that doesn't require channel reciprocity, and that alleviates the need to alternate between the forward and reverse network as is the case in Distributed IA (Gomadam, Cadambe, Jafar 08'), thereby inducing significant overhead in certain environments where the channel changes frequently. Most importantly, our effort is focused on ensuring that this one-sided approach does not degrade the performance of the system w.r.t. Distributed IA (since it cannot improve it). As a first step, we model the interference in each receiver's desired signal as a function of the transmitters' beamforming vectors. We then propose a simple steepest descent (SD) algorithm and use it to minimize the inter...

  14. Interference Alignment with Partially Coordinated Transmit Precoding

    CERN Document Server

    Yousafzai, Aimal Khan

    2011-01-01

    In this paper, we introduce an efficient interference alignment (IA) algorithm exploiting partially coordinated transmit precoding to improve the number of concurrent interference-free transmissions, i.e., the multiplexing gain, in multicell downlink. The proposed coordination model is such that each base-station simultaneously transmits to two users and each user is served by two base-stations. First, we show in a K-user system operating at the information theoretic upper bound of degrees of freedom (DOF), the generic IA is proper when $K \\leq 3$, whereas the proposed partially coordinated IA is proper when $K \\leq 5$. Then, we derive a non-iterative, i.e., one shot, IA algorithm for the proposed scheme when $K \\leq 5$. We show that for a given latency, the backhaul data rate requirement of the proposed method grows linearly with K. Monte-Carlo simulation results show that the proposed one-shot algorithm offers higher system throughput than the iterative IA at practical SNR levels.

  15. Phase-locked laser coherent interference

    Institute of Scientific and Technical Information of China (English)

    Jingjing Wang; Xiaobo Wang; Bo He; Liantuan Mao; Suotang Jia

    2011-01-01

    A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated. It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system. After phase locking using the phase modulating and lock-in technique, the drift of the relative phase is focalized around ±0.0016 rad and the fringe visibility is restricted to 2×l0-4.%@@ A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated.It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system.After phase locking using the vhase modulating and lock-in technique.the drift of the relative phase is focalized around±0.0016 rad and the fringe visibility is restricted to 2×10-4.

  16. RNA interference: Antiviral weapon and beyond

    Institute of Scientific and Technical Information of China (English)

    Quan-Chu Wang; Qing-He Nie; Zhi-Hua Feng

    2003-01-01

    RNA interference (RNAi) is a remarkable type of gene regulation based on sequence-specific targeting and degradation of RNA. The term encompasses related pathways found in a broad range of eukaryotic organisms, including fungi, plants, and animals. RNA interference is part of a sophisticated network of interconnected pathways for cellular defense, RNA surveillance, and development and it may become a powerful tool to manipulate gene expression experimentally. RNAi technology is currently being evaluated not only as an extremely powerful instrument for functional genomic analyses, but also as a potentially useful method to develop specific dsRNA based gene-silencing therapeutics.Several laboratories have been interested in using RNAi to control viral infection and many reports in Nature and in Cell show that short interfering (si) RNAs can inhibit infection by HIV-1, polio and hepatitis C viruses in a sequence-specific manner. RNA-based strategies for gene inhibition in mammalian cells have recently been described, which offer the promise of antiviral therapy.

  17. CP violation: Dalitz interference, CPT and FSI

    CERN Document Server

    Nogueira, J H Alvarenga; Cavalcante, A B R; Frederico, T; Lourenço, O

    2015-01-01

    Resonances and final state interactions (FSI) play a role in the formation of CP violation (CPV) constrained by CPT invariance. We provide a general formulation of CPV including resonances and FSI starting from the CPT constraint. Our discussion is elaborated within a simple $B$ decay model with the $\\rho$ and $f_0(980)$ resonances plus a non resonant background including the $\\pi\\pi \\to KK$ coupled amplitude. We consider few illustrative examples to show the interference patterns appearing in the CP asymmetry, namely, that from the $\\rho$ resonance plus a non-resonant amplitude, and that from the interference of the $\\rho$ and $f_0(980)$ resonances. We perform the fit of the CP asymmetry for the charmless three-body $B^\\pm$ decay channel $B^{\\pm}\\to \\pi^{\\pm} \\pi^+\\pi^-$ and obtain as outcome the $B^{\\pm}\\to \\pi^{\\pm} K^+K^-$ for $\\pi\\pi$ channel asymmetry in the mass region below $1.6$~GeV in fair agreement with the new data LHCb data. Analogously, we also describe the CP asymmetry of the $B^\\pm\\to K^\\pm\\pi...

  18. Absence of auditory 'global interference' in autism.

    Science.gov (United States)

    Foxton, Jessica M; Stewart, Mary E; Barnard, Louise; Rodgers, Jacqui; Young, Allan H; O'Brien, Gregory; Griffiths, Timothy D

    2003-12-01

    There has been considerable recent interest in the cognitive style of individuals with Autism Spectrum Disorder (ASD). One theory, that of weak central coherence, concerns an inability to combine stimulus details into a coherent whole. Here we test this theory in the case of sound patterns, using a new definition of the details (local structure) and the coherent whole (global structure). Thirteen individuals with a diagnosis of autism or Asperger's syndrome and 15 control participants were administered auditory tests, where they were required to match local pitch direction changes between two auditory sequences. When the other local features of the sequence pairs were altered (the actual pitches and relative time points of pitch direction change), the control participants obtained lower scores compared with when these details were left unchanged. This can be attributed to interference from the global structure, defined as the combination of the local auditory details. In contrast, the participants with ASD did not obtain lower scores in the presence of such mismatches. This was attributed to the absence of interference from an auditory coherent whole. The results are consistent with the presence of abnormal interactions between local and global auditory perception in ASD.

  19. Normalized GNSS interference pattern technique for altimetry.

    Science.gov (United States)

    Ribot, Miguel Angel; Kucwaj, Jean-Christophe; Botteron, Cyril; Reboul, Serge; Stienne, Georges; Leclère, Jérôme; Choquel, Jean-Bernard; Farine, Pierre-André; Benjelloun, Mohammed

    2014-06-11

    It is well known that reflected signals from Global Navigation Satellite Systems (GNSS) can be used for altimetry applications, such as monitoring of water levels and determining snow height. Due to the interference of these reflected signals and the motion of satellites in space, the signal-to-noise ratio (SNR) measured at the receiver slowly oscillates. The oscillation rate is proportional to the change in the propagation path difference between the direct and reflected signals, which depends on the satellite elevation angle. Assuming a known receiver position, it is possible to compute the distance between the antenna and the surface of reflection from the measured oscillation rate. This technique is usually known as the interference pattern technique (IPT). In this paper, we propose to normalize the measurements in order to derive an alternative model of the SNR variations. From this model, we define a maximum likelihood estimate of the antenna height that reduces the estimation time to a fraction of one period of the SNR variation. We also derive the Cramér-Rao lower bound for the IPT and use it to assess the sensitivity of different parameters to the estimation of the antenna height. Finally, we propose an experimental framework, and we use it to assess our approach with real GPS L1 C/A signals.

  20. Interference Channels with Rate-Limited Feedback

    CERN Document Server

    Vahid, Alireza; Avestimehr, Amir Salman

    2011-01-01

    We study the effect of rate-limited feedback on the capacity region of the two-user interference channel. We consider three different interference models: El Gamal-Costa deterministic model, the linear deterministic model, and the Gaussian model. For the first two models, we develop an achievable scheme that combines three techniques: Han-Kobayashi message splitting, quantize-and-binning, and partial decode-and-forward. We also derive new outer-bounds to show the optimality of our scheme under the linear deterministic model. For the Gaussian model, we establish outer-bounds on the capacity region with rate-limited feedback. Employing lattice codes and the ideas developed in the first two models, we also propose a transmission strategy for the Gaussian model. For symmetric channel gains, we prove that the gap between the achievable sum-rate of the proposed scheme and the outer-bound is bounded by a constant number of bits, independent of the channel gains.

  1. New Interference Mechanism Controls Ultracold Chemistry

    Science.gov (United States)

    Kendrick, Brian K.; Hazra, Jisha; Balakrishnan, N.

    2016-05-01

    A newly discovered interference mechanism has been shown to control the outcome of ultracold chemical reactions. The mechanism originates from the unique properties associated with ultracold collisions, namely: (1) isotropic (s-wave) scattering and (2) an effective quantization of the scattering phase shift (which originates from the bound state structure of the molecule). These two properties can lead to maximum constructive or destructive interference between two interfering reaction pathways (such as exchange and non-exchange in systems with two or more identical nuclei). If the molecular system exhibits a conical intersection, then the associated geometric phase is shown to act as a ``quantum switch'' which can turn the reactivity on or off. Reaction rate coefficients for the O + OH --> H + O2 and H + H2, reactions are presented which explicitly demonstrate the effect. Experimentalists might exploit this new mechanism to control ultracold reactions by the application of external electric or magnetic fields or by the selection of a particular nuclear spin state. This work was supported in part by the LDRD program (Grant No. 20140309ER) at LANL (B.K.) and by NSF Grant PHY-1505557 (N.B.) and ARO MURI Grant No. W911NF-12-1-0476 (N.B.).

  2. Carbon Disulfide (CS2) Interference in Glucose Metabolism from Unconventional Oil and Gas Extraction and Processing Emissions.

    Science.gov (United States)

    Rich, Alisa L; Patel, Jay T; Al-Angari, Samiah S

    2016-01-01

    Carbon disulfide (CS2) has been historically associated with the manufacturing of rayon, cellophane, and carbon tetrachloride production. This study is one of the first to identify elevated atmospheric levels of CS2 above national background levels and its mechanisms to dysregulate normal glucose metabolism. Interference in glucose metabolism can indirectly cause other complications (diabetes, neurodegenerative disease, and retinopathy), which may be preventable if proper precautions are taken. Rich et al found CS2 and 12 associated sulfide compounds present in the atmosphere in residential areas where unconventional shale oil and gas extraction and processing operations were occurring. Ambient atmospheric concentrations of CS2 ranged from 0.7 parts per billion by volume (ppbv) to 103 ppbv over a continuous 24-hour monitoring period. One-hour ambient atmospheric concentrations ranged from 3.4 ppbv to 504.6 ppbv. Using the U.S. Environmental Protection Agency Urban Air Toxic Monitoring Program study as a baseline comparison for atmospheric CS2 concentrations found in this study, it was determined that CS2 atmospheric levels were consistently elevated in areas where unconventional oil and gas extraction and processing occurred. The mechanisms by which CS2 interferes in normal glucose metabolism by dysregulation of the tryptophan metabolism pathway are presented in this study. The literature review found an increased potential for alteration of normal glucose metabolism in viscose rayon occupational workers exposed to CS2. Occupational workers in the energy extraction industry exposed to CS2 and other sulfide compounds may have an increased potential for glucose metabolism interference, which has been an indicator for diabetogenic effect and other related health impacts. The recommendation of this study is for implementation of regular monitoring of blood glucose levels in CS2-exposed populations as a preventative health measure.

  3. On the Optimality of Opportunistic Interference Alignment in 3-Transmitter MIMO Interference Channels

    CERN Document Server

    Lee, Jung Hoon; Love, David J

    2011-01-01

    In this paper, we propose opportunistic interference alignment (OIA) for three-transmitter multiple-input multiple-output (MIMO) interference channels (ICs). In the proposed OIA scheme, each transmitter has its own user group that consists of $K$ users, and each transmitter opportunistically selects the user whose received interference signals are most aligned. Thus, three-transmitter MIMO IC is opportunistically constructed by three transmitters and their selected users. Contrary to conventional IA, perfect channel information for all of the interference links is not required at the transmitter. Each user just needs to feed back one scalar value in the proposed OIA scheme. When the number of receive antennas is $N_R$ (with $N_R=2M$) and the number of transmit antennas is $N_T$ (with $N_T\\ge M$), we prove that each transmitter can achieve $M$ degrees of freedom (DoF) as the number of users in each group goes to infinity ($K\\to\\infty$), in comparison with the $\\frac{2M}{3}$ DoF known to be achievable in the th...

  4. GNSS space-time interference mitigation and attitude determination in the presence of interference signals.

    Science.gov (United States)

    Daneshmand, Saeed; Jahromi, Ali Jafarnia; Broumandan, Ali; Lachapelle, Gérard

    2015-05-26

    The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios.

  5. Degeneracy estimation in interference models on wireless networks

    Science.gov (United States)

    McBride, Neal; Bulava, John; Galiotto, Carlo; Marchetti, Nicola; Macaluso, Irene; Doyle, Linda

    2017-03-01

    We present a Monte Carlo study of interference in real-world wireless networks using the Potts model. Our approach maps the Potts energy to discrete interference levels. These levels depend on the configurations of radio frequency allocation in the network. For the first time, we estimate the degeneracy of these interference levels using the Wang-Landau algorithm. The cumulative distribution function of the resulting density of states is found to increase rapidly at a critical interference value. We compare these critical values for several different real-world interference networks and Potts models. Our results show that models with a greater number of available frequency channels and less dense interference networks result in the majority of configurations having lower interference levels. Consequently, their critical interference levels occur at lower values. Furthermore, the area under the density of states increases and shifts to lower interference values. Therefore, the probability of randomly sampling low interference configurations is higher under these conditions. This result can be used to consider dynamic and distributed spectrum allocation in future wireless networks.

  6. In-flight observations of electromagnetic interferences emitted by satellite

    Institute of Scientific and Technical Information of China (English)

    CAO JinBin; YANG JunYing; YUAN ShiGan; SHEN XuHui; LIU YuanMo; YAN ChunXiao; LI WenZhen; CHEN Tao

    2009-01-01

    Using the data from STAFF/TC-1, this paper for the first time analyzes the electromagnetic interferences of Chinese scientific satellite. The electromagnetic interference of satellite exists mainly below 30 Hz,but can extend to 190 Hz with an obviously decreasing power spectral density. The electromagnetic interferences at frequencies below 190 Hz have good correlation with the solar aspect angle. The electromagnetic interferences at frequencies between 190 and 830 Hz have also correlation with solar aspect angle. However, the electromagnetic interferences at frequencies above 830 Hz have no correlation with the solar aspect angle. The correlation coefficient between solar aspect angel and electromagnetic interferences is around 0.90. The larger the solar aspect angle, the stronger the satellite electromagnetic interference. When the solar aspect angle increases from 90.6° to 93.6°, the electromagnetic interferences at frequencies <10 Hz increase by 8 times and those at frequencies 190-830 Hz increase by 60%. This close association of electromagnetic interferences with the solar aspect angle indicates that the solar aspect angle is the main factor to determine the electromagnetic interferences.The electromagnetic interferences of satellite in sunlight are larger than those in eclipse. The electromagnetic interference produced by solar panel occupies about 87% in the low frequency bend (<100 Hz)and 94% in the high frequency band (>100 Hz) of the total electromagnetic interference produced by satellite. These in flight observations of electromagnetic radiation of satellites will be very helpful to the designs of future satellites of space sciences or earthquake sciences.

  7. In-flight observations of electromagnetic interferences emitted by satellite

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Using the data from STAFF/TC-1, this paper for the first time analyzes the electromagnetic interferences of Chinese scientific satellite. The electromagnetic interference of satellite exists mainly below 30 Hz, but can extend to 190 Hz with an obviously decreasing power spectral density. The electromagnetic interferences at frequencies below 190 Hz have good correlation with the solar aspect angle. The electromagnetic interferences at frequencies between 190 and 830 Hz have also correlation with solar as-pect angle. However, the electromagnetic interferences at frequencies above 830 Hz have no correlation with the solar aspect angle. The correlation coefficient between solar aspect angel and electromagnetic interferences is around 0.90. The larger the solar aspect angle, the stronger the satellite electromagnetic interference. When the solar aspect angle increases from 90.6° to 93.6°, the electromagnetic interferences at frequencies <10 Hz increase by 8 times and those at frequencies 190―830 Hz increase by 60%. This close association of electromagnetic interferences with the solar aspect angle indicates that the solar aspect angle is the main factor to determine the electromagnetic interferences. The electromagnetic interferences of satellite in sunlight are larger than those in eclipse. The electro-magnetic interference produced by solar panel occupies about 87% in the low frequency band (<100 Hz) and 94% in the high frequency band (>100 Hz) of the total electromagnetic interference produced by satellite. These in flight observations of electromagnetic radiation of satellites will be very helpful to the designs of future satellites of space sciences or earthquake sciences.

  8. Atmospheric Channel Characteristics for Quantum Communication with Continuous Polarization Variables

    CERN Document Server

    Heim, Bettina; Bartley, Tim; Sabuncu, Metin; Wittmann, Christoffer; Sych, Denis; Marquardt, Christoph; Leuchs, Gerd

    2009-01-01

    We investigate the properties of an atmospheric channel for free space quantum communication with continuous polarization variables. In our prepare-and-measure setup, coherent polarization states are transmitted through an atmospheric quantum channel of 100m length on the roof of our institute's building. The signal states are measured by homodyne detection with the help of a local oscillator (LO) which propagates in the same spatial mode as the signal, orthogonally polarized to it. Thus the interference of signal and LO is excellent and atmospheric fluctuations are autocompensated. The LO also acts as spatial and spectral filter, which allows for unrestrained daylight operation. Important characteristics for our system are atmospheric channel influences that could cause polarization, intensity and position excess noise. Therefore we study these influences in detail. Our results indicate that the channel is suitable for our quantum communication system in most weather conditions.

  9. Wavefront dislocations of Gaussian beams nesting optical vortices in a turbulent atmosphere

    Institute of Scientific and Technical Information of China (English)

    Yixin Zhang(张逸新); Chunkan Tao(陶纯堪)

    2004-01-01

    A phase singularity of the light field created by interference of two Gaussian singular beams which propagate in a weak and near ground turbulent atmosphere is analyzed by the Rytov approximation and the short-term averaging method of the dislocation-position. We demonstrate that an edge or circular dislocation may be formed by both parallel and coaxial or noncoaxial collimated beams with different or equal beam-width interfere. The edge or circular short-term wavefront dislocations of super position field depend on the atmospheric turbulence strength, beam propagation distance, amplitude ratio, dislocation of nesting vortices, and beam-width or beam-width ratio of the individual beams.

  10. Quantum interference between transverse spatial waveguide modes

    Science.gov (United States)

    Mohanty, Aseema; Zhang, Mian; Dutt, Avik; Ramelow, Sven; Nussenzveig, Paulo; Lipson, Michal

    2017-01-01

    Integrated quantum optics has the potential to markedly reduce the footprint and resource requirements of quantum information processing systems, but its practical implementation demands broader utilization of the available degrees of freedom within the optical field. To date, integrated photonic quantum systems have primarily relied on path encoding. However, in the classical regime, the transverse spatial modes of a multi-mode waveguide have been easily manipulated using the waveguide geometry to densely encode information. Here, we demonstrate quantum interference between the transverse spatial modes within a single multi-mode waveguide using quantum circuit-building blocks. This work shows that spatial modes can be controlled to an unprecedented level and have the potential to enable practical and robust quantum information processing. PMID:28106036

  11. Quantum interference between transverse spatial waveguide modes

    Science.gov (United States)

    Mohanty, Aseema; Zhang, Mian; Dutt, Avik; Ramelow, Sven; Nussenzveig, Paulo; Lipson, Michal

    2017-01-01

    Integrated quantum optics has the potential to markedly reduce the footprint and resource requirements of quantum information processing systems, but its practical implementation demands broader utilization of the available degrees of freedom within the optical field. To date, integrated photonic quantum systems have primarily relied on path encoding. However, in the classical regime, the transverse spatial modes of a multi-mode waveguide have been easily manipulated using the waveguide geometry to densely encode information. Here, we demonstrate quantum interference between the transverse spatial modes within a single multi-mode waveguide using quantum circuit-building blocks. This work shows that spatial modes can be controlled to an unprecedented level and have the potential to enable practical and robust quantum information processing.

  12. Onomastic Interferences in the Language of Migration

    Directory of Open Access Journals (Sweden)

    Ioana Jieanu

    2015-12-01

    Full Text Available In case of bilingual speakers, proper names undergo different transformations, depending on the contextual character of a manifestation of meanings, “the relationship between the proper name and the denoted object being temporary, dependent on the verbal and situational context” (Tomescu 1998: 1. Within the scope of the current economic migration of Romanians to Spain and Italy, the names of Romanian people have undergone various modifications under the influence of Spanish and Italian onomastics. In the present work, the performance of two main tasks is described: an analysis of the interferences which emerge within communication, in case of the proper names of Romanian people who have emigrated to Spain and Italy; and classification of the proper names of new-born children within Romanian families that have settled in these countries.

  13. Symbiont-mediated RNA interference in insects.

    Science.gov (United States)

    Whitten, Miranda M A; Facey, Paul D; Del Sol, Ricardo; Fernández-Martínez, Lorena T; Evans, Meirwyn C; Mitchell, Jacob J; Bodger, Owen G; Dyson, Paul J

    2016-02-24

    RNA interference (RNAi) methods for insects are often limited by problems with double-stranded (ds) RNA delivery, which restricts reverse genetics studies and the development of RNAi-based biocides. We therefore delegated to insect symbiotic bacteria the task of: (i) constitutive dsRNA synthesis and (ii) trauma-free delivery. RNaseIII-deficient, dsRNA-expressing bacterial strains were created from the symbionts of two very diverse pest species: a long-lived blood-sucking bug, Rhodnius prolixus, and a short-lived globally invasive polyphagous agricultural pest, western flower thrips (Frankliniella occidentalis). When ingested, the manipulated bacteria colonized the insects, successfully competed with the wild-type microflora, and sustainably mediated systemic knockdown phenotypes that were horizontally transmissible. This represents a significant advance in the ability to deliver RNAi, potentially to a large range of non-model insects.

  14. RNA interference: past, present and future.

    Science.gov (United States)

    Campbell, Tessa N; Choy, Francis Y M

    2005-01-01

    RNA interference (RNAi) is the sequence-specific gene silencing induced by double-stranded RNA. RNAi is mediated by 21-23 nucleotide small interfering RNAs (siRNAs) which are produced from long double-stranded RNAs by RNAse II-like enzyme Dicer. The resulting siRNAs are incorporated into a RNA-induced silencing complex (RISC) that targets and cleaves mRNA complementary to the siRNAs. Since its inception in 1998, RNAi has been demonstrated in organisms ranging from trypanosomes to nematodes to vertebrates. Potential uses already in progress include the examination of specific gene function in living systems, the development of anti-viral and anti-cancer therapies, and genome-wide screens. In this review, we discuss the landmark discoveries that established the contextual framework leading up to our current understanding of RNAi. We also provide an overview of current developments and future applications.

  15. Interference theory of metamaterial perfect absorbers

    CERN Document Server

    Chen, Hou-Tong

    2011-01-01

    The impedance matching in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with a direct evidence from the anti-parallel directions of surface currents in the metal structures. Here we present a different theoretical interpretation based on interferences, which shows that the two layers of metal structure in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

  16. Time-domain quantum interference in graphene

    Science.gov (United States)

    Fillion-Gourdeau, François; Gagnon, Denis; Lefebvre, Catherine; MacLean, Steve

    2016-09-01

    The electron momentum density obtained from the Schwinger-like mechanism is evaluated for a graphene sample immersed in a homogeneous time-dependent electric field. Based on the analogy between graphene low-energy electrons and quantum electrodynamics (QED), numerical techniques borrowed from strong field QED are employed and compared to approximate analytical approaches. It is demonstrated that for some range of experimentally accessible parameters, the pair production proceeds by sequences of adiabatic evolutions followed by nonadiabatic Landau-Zener transitions, reminiscent of the Kibble-Zurek mechanism describing topological defect density in second order phase transitions. For some field configurations, this yields interference patterns in momentum space which are explained in terms of the adiabatic-impulse model and the Landau-Zener-Stückelberg interferometry.

  17. RNA interference in neuroscience: progress and challenges.

    Science.gov (United States)

    Miller, Victor M; Paulson, Henry L; Gonzalez-Alegre, Pedro

    2005-12-01

    1.RNA interference (RNAi) is a recently discovered biological pathway that mediates post-transcriptional gene silencing. The process of RNAi is orchestrated by an increasingly well-understood cellular machinery. 2. The common entry point for both natural and engineered RNAi are double stranded RNA molecules known as short interfering RNAs (siRNAs), that mediate the sequence-specific identification and degradation of the targeted messenger RNA (mRNA). The study and manipulation of these siRNAs has recently revolutionized biomedical research. 3. In this review, we first provide a brief overview of the process of RNAi, focusing on its potential role in brain function and involvement in neurological disease. We then describe the methods developed to manipulate RNAi in the laboratory and its applications to neuroscience. Finally, we focus on the potential therapeutic application of RNAi to neurological disease.

  18. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  19. Scattering and interference in epitaxial graphene.

    Science.gov (United States)

    Rutter, G M; Crain, J N; Guisinger, N P; Li, T; First, P N; Stroscio, J A

    2007-07-13

    A single sheet of carbon, graphene, exhibits unexpected electronic properties that arise from quantum state symmetries, which restrict the scattering of its charge carriers. Understanding the role of defects in the transport properties of graphene is central to realizing future electronics based on carbon. Scanning tunneling spectroscopy was used to measure quasiparticle interference patterns in epitaxial graphene grown on SiC(0001). Energy-resolved maps of the local density of states reveal modulations on two different length scales, reflecting both intravalley and intervalley scattering. Although such scattering in graphene can be suppressed because of the symmetries of the Dirac quasiparticles, we show that, when its source is atomic-scale lattice defects, wave functions of different symmetries can mix.

  20. Narrowband interference parameterization for sparse Bayesian recovery

    KAUST Repository

    Ali, Anum

    2015-09-11

    This paper addresses the problem of narrowband interference (NBI) in SC-FDMA systems by using tools from compressed sensing and stochastic geometry. The proposed NBI cancellation scheme exploits the frequency domain sparsity of the unknown signal and adopts a Bayesian sparse recovery procedure. This is done by keeping a few randomly chosen sub-carriers data free to sense the NBI signal at the receiver. As Bayesian recovery requires knowledge of some NBI parameters (i.e., mean, variance and sparsity rate), we use tools from stochastic geometry to obtain analytical expressions for the required parameters. Our simulation results validate the analysis and depict suitability of the proposed recovery method for NBI mitigation. © 2015 IEEE.

  1. Atmospheric Habitable Zones in Y Dwarf Atmospheres

    CERN Document Server

    Yates, Jack S; Biller, Beth; Cockell, Charles S

    2016-01-01

    We use a simple organism lifecycle model to explore the viability of an atmospheric habitable zone (AHZ), with temperatures that could support Earth-centric life, which sits above an environment that does not support life. We illustrate this idea using the object WISE J085510.83-0714442.5, which is a cool, free-floating brown dwarf. We allow organisms to adapt to their atmospheric environment (described by temperature, convection, and gravity) by adopting different growth strategies that maximize their chance of survival and proliferation. We assume a constant upward vertical velocity through the AHZ. We found that the organism growth strategy is most sensitive to the magnitude of the atmospheric convection. Stronger convection supports the evolution of more massive organisms. For a purely radiative environment we find that evolved organisms have a mass that is an order of magnitude smaller than terrestrial microbes, thereby defining a dynamical constraint on the dimensions of life that an AHZ can support. Ba...

  2. Increased Stroop interference with better second-language reading skill.

    Science.gov (United States)

    Braet, Wouter; Noppe, Nele; Wagemans, Johan; Op de Beeck, Hans

    2011-03-01

    Skilled readers demonstrate remarkable efficiency in processing written words, unlike beginning readers for whom reading occurs more serially and places higher demands on visual attention. In the present study, we used the Stroop paradigm to investigate the relationship between reading skill and automaticity, in individuals learning a second language with a different orthographic system. Prior studies using this paradigm have presented a mixed picture, finding a positive, a negative, or no relationship between the size of Stroop interference and reading skills. Our results show that Stroop interference in the second language was positively related to reading skill (when controlled for interference in the first language). Furthermore, interference was positively related to objective but not subjective indices of the amount of exposure to the second language. We suggest that the lack of consistency in the results of earlier studies may be due, at least in part, to these studies looking at Stroop interference in isolation, rather than comparing interference between languages.

  3. Abstract Certification of Global Non-Interference in Rewriting Logic

    CERN Document Server

    Alba-Castro, Mauricio; Escobar, Santiago

    2010-01-01

    Non-interference is a semantic program property that assigns confidentiality levels to data objects and prevents illicit information flows from occurring from high to low security levels. In this paper, we present a novel security model for global non-interference which approximates non-interference as a safety property. We also propose a certification technique for global non-interference of complete Java classes based on rewriting logic, a very general logical and semantic framework that is efficiently implemented in the high-level programming language Maude. Starting from an existing Java semantics specification written in Maude, we develop an extended, information-flow Java semantics that allows us to correctly observe global non-interference policies. In order to achieve a finite state transition system, we develop an abstract Java semantics that we use for secure and effective non-interference Java analysis. The analysis produces certificates that are independently checkable and are small enough to be u...

  4. Cognitive Aware Interference Mitigation Scheme for LTE Femtocells

    KAUST Repository

    Alqerm, Ismail

    2015-04-21

    Femto-cells deployment in today’s cellular networks came into practice to fulfill the increasing demand for data services. However, interference to other femto and macro-cells users remains an unresolved challenge. In this paper, we propose an interference mitigation scheme to control the cross-tier interference caused by femto-cells to the macro users and the co-tier interference among femtocells. Cognitive radio spectrum sensing capability is utilized to determine the non-occupied channels or the ones that cause minimal interference to the macro users. An awareness based channel allocation scheme is developed with the assistance of the graph-coloring algorithm to assign channels to the femto-cells base stations with power optimization, minimal interference, maximum throughput, and maximum spectrum efficiency. In addition, the scheme exploits negotiation capability to match traffic load and QoS with the channel capacity, and to maintain efficient utilization of the available channels.

  5. Cooperative Precoding with Limited Feedback for MIMO Interference Channels

    CERN Document Server

    Huang, Kaibin

    2010-01-01

    Multi-antenna precoding effectively mitigates the interference in wireless networks. However, the resultant performance gains can be significantly compromised in practice if the precoder design fails to account for the inaccuracy in the channel state information (CSI) feedback. This paper addresses this issue by considering finite-rate CSI feedback from receivers to their interfering transmitters in the two-user multiple-input-multiple-output (MIMO) interference channel, called \\emph{cooperative feedback}, and proposing a systematic precoder design. Specifically, each precoder is decomposed into inner and outer precoders for nulling interference and improving the data-link array gain, respectively. The inner precoders are further designed to suppress the residual interference resulting from the finite-rate cooperative feedback. To regulate such interference, additional scalar cooperative feedback signals are designed to control transmission power using different criteria including fixed interference margins, ...

  6. Quantum Interference in Time-Delayed Nonsequential Double Ionization

    CERN Document Server

    Maxwell, A S

    2015-01-01

    We perform a systematic analysis of quantum interference in nonsequential double ionization focusing on the recollision-excitation with subsequent ionization (RESI) mechanism, employing the strong-field approximation (SFA). We find that interference has a major influence on the shape, localization and symmetry of the correlated electron momentum distributions. In particular, the fourfold symmetry with regard to the parallel momentum components observed in previous SFA studies is broken. Two types of interference are observed and thoroughly analyzed, namely that caused by electron indistinguishability and intra-cycle events, and that stemming from different excitation channels. We find that interference is most prominent around the diagonal and anti-diagonal in the parallel-momentum plane and provide fully analytical expressions for most interference patterns encountered. We also show that this interference can be controlled by an appropriate choice of phase and excited-state geometry. This leads a to myriad o...

  7. Measurement of the Atmospheric $\

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beattie, K; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Bell, M; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose1, D; Boser, S; Botner, O; Brayeur, L; Brown, A M; Bruijn, R; Brunner, J; Buitink, S; Carson, M; Casey, J; Casier, M; Chirkin, D; Christy, B; Clark, K; Clevermann, F; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Diaz-Velez, J C; Dreyer, J; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glusenkamp, T; Goldschmidt, A; Golup, G; Goodman, J A; Gora, D; Grant, D; Gross, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heimann, P; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jlelati, O; Kappes, A; Karg, T; Karle, A; Kiryluk, J; Kislat, F; Klas, J; Klein, S R; Kohne, J -H; Kohnen, G; Kolanoski, H; Kopke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lauer, R; Lesiak-Bzdak, M; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meszaros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Pepper, J A; Heros, C Perez de los; Pieloth, D; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Radel, L; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schoneberg, S; Schonherr, L; Schonwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Seo, S H; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soiron, M; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stoss, A; Strahler, E A; Strom, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge1, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wasserman, R; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zilles, A; Zoll, M

    2012-01-01

    We report the first observation in a high energy neutrino telescope of cascades induced by atmospheric electron neutrinos and by neutral current interactions of atmospheric neutrinos of all flavors. Using data recorded during the first year of operation of IceCube's DeepCore low energy extension, a sample of 1029 events is observed in 281 days of data. The number of observed cascades is $N_{\\rm cascade} = 496 \\pm 66 (stat.) \\pm 88(syst.)$ and the rest of the sample consists of residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is determined in the energy range between approximately 80 GeV and 6 TeV and is consistent with models of atmospheric neutrinos.

  8. Atmospheric Circulation of Exoplanets

    CERN Document Server

    Showman, Adam P; Menou, Kristen

    2009-01-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric d...

  9. Quasiparticle interference in unconventional 2D systems

    Science.gov (United States)

    Chen, Lan; Cheng, Peng; Wu, Kehui

    2017-03-01

    At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe2), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.

  10. Cross Layer Interference Management in Wireless Biomedical Networks

    OpenAIRE

    Spanakis, Emmanouil G.; Vangelis Sakkalis; Kostas Marias; Apostolos Traganitis

    2014-01-01

    Interference, in wireless networks, is a central phenomenon when multiple uncoordinated links share a common communication medium. The study of the interference channel was initiated by Shannon in 1961 and since then this problem has been thoroughly elaborated at the Information theoretic level but its characterization still remains an open issue. When multiple uncoordinated links share a common medium the effect of interference is a crucial limiting factor for network performance. In this wo...

  11. Dynamic Resource Coordination and Interference Management for Femtocell Networks

    CERN Document Server

    Liang, Yan; Yang, Chunliang

    2010-01-01

    Femtocell is emerging as a key technology to secure the coverage and capacity in indoor environments. However the deployment of a new femtocell layer may originate undesired interference to the whole system. This paper investigates spectrum resource coordination and interference management for the femtocell networks. A resource coordination scheme based on broadcasting resource coordination request messages by the femto mobile is proposed to reduce the system interference.

  12. Interference in wireless ad hoc networks with smart antennas

    KAUST Repository

    Alabdulmohsin, Ibrahim

    2014-08-01

    In this paper, we show that the use of directional antennas in wireless ad hoc networks can actually increase interference due to limitations of virtual carrier sensing. We derive a simple mathematical expression for interference in both physical and virtual carrier sense networks, which reveals counter-intuitively that receivers in large dense networks with directional antennas can experience larger interference than in omnidirectional networks unless the beamwidth is sufficiently small. Validity of mathematical analysis is confirmed using simulations.

  13. Interference cancellation technique under imperfect synchronization in cellular systems

    Institute of Scientific and Technical Information of China (English)

    WANG; Xin; WU; Zhuo

    2009-01-01

    In this paper, an asynchronous cooperative cellular system applied with space-time block coding(STBC)is investigated. A signal detector is proposed based on parallel interference cancellation(PIC), to cancel the inter-symbol interference(ISI)caused by the imperfect synchronization. Simulation results show that the proposed PIC detector can effectively suppress the ISI, but there is still a comparatively high error floor, due to the co-channel interference(CCI)of the cellular system.

  14. Interference Assembly and Fretting Wear Analysis of Hollow Shaft

    OpenAIRE

    Chuanjun Han; Jie Zhang

    2014-01-01

    Fretting damage phenomenon often appears in the interference fit assembly. The finite element model of hollow shaft and shaft sleeve was established, and the equivalent stress and contact stress were computed after interference assembly. The assembly body of hollow shaft and shaft sleeve was in whirling bending load, and the contact status (sticking, sliding, and opening) and the distribution of stress along one typical contact line were computed under different loads, interferences, hollow d...

  15. Atmospheric Measurements Laboratory (AML)

    Data.gov (United States)

    Federal Laboratory Consortium — The Atmospheric Measurements Laboratory (AML) is one of the nation's leading research facilities for understanding aerosols, clouds, and their interactions. The AML...

  16. Pulse-level interference and meteor processing of Arecibo ISR data

    Science.gov (United States)

    Wen, C.-H.; Briczinski, S. J.; Livneh, D. J.; Doherty, J. F.; Mathews, J. D.

    2007-07-01

    We introduce a simple but effective order statistics filter for the pulse-level interference and meteor processing of Arecibo ionosphere observation data. Using this filter and the techniques introduced by Wen et al. [2005. Adaptive filtering for the separation of incoherent scatter and meteor signals for Arecibo Observation Data. Journal of Atmospheric and Solar-Terrestrial Physics 67, 1190 1195] we effectively remove/separate the unwanted signals, such as impulsive interference and meteor returns, encountered during incoherent scatter radar (ISR) observations of the ionosphere. We further analyze the separated signals to obtain uniquely “cleaned” incoherent scatter power data and scientifically valuable meteor parameters. We present the processed incoherent scatter results from 22/23 March 2004 observations and the altitude and the speed distributions of the separated meteor signals. The nighttime photochemical E-region is clearly revealed for the first time as a result of meteor and interference removal. Additionally, these results reveal the first major bias in large aperture radar meteor headecho results—the meteor speed distribution is flattened by the absence of at least 50% of the events with duration less than 10 ms revealed by meteor-specific observations. Meteor data derived from standard incoherent scatter data always displays this bias.

  17. Reconstruction of Interfering Waves from Three Dimensional Analysis of Their Interference Pattern

    Directory of Open Access Journals (Sweden)

    M. T. Tavassoli

    1997-04-01

    Full Text Available   Optical interferometry is being used as an efficient tool to analyse smooth surfaces for more than a century. Although, due to introduction of novel computer assisted analyzing techniques and array detectors, like CCD, the speed and the precision of processing have been increased tremendously, but the main equation involved is not changed. The main equation is the intensity distribution in the interference pattern of a plane reference wave and the required wave.   In the paper it is shown that by analysis of the interference pattern of two unknown waves in three dimension (which is possible for coherent waves it is possible to reconstruct each wave separately. This approach has several useful applications, namely, on can do without reference plane wave in the interferometric surface analysis and, it is possible to reconstruct an unknown wave by making it to interfere with itself. This is very useful in determining the profile of laser beams and erasing the effect of atmospheric disturbances on observing astronomical objects.

  18. The right posterior paravermis and the control of language interference.

    Science.gov (United States)

    Filippi, Roberto; Richardson, Fiona M; Dick, Frederic; Leech, Robert; Green, David W; Thomas, Michael S C; Price, Cathy J

    2011-07-20

    Auditory and written language in humans' comprehension necessitates attention to the message of interest and suppression of interference from distracting sources. Investigating the brain areas associated with the control of interference is challenging because it is inevitable that activation of the brain regions that control interference co-occurs with activation related to interference per se. To isolate the mechanisms that control verbal interference, we used a combination of structural and functional imaging techniques in Italian and German participants who spoke English as a second language. First, we searched structural MRI images of Italian participants for brain regions in which brain structure correlated with the ability to suppress interference from the unattended dominant language (Italian) while processing heard sentences in their weaker language (English). This revealed an area in the posterior paravermis of the right cerebellum in which gray matter density was higher in individuals who were better at controlling verbal interference. Second, we found functional activation in the same region when our German participants made semantic decisions on written English words in the presence of interference from unrelated words in their dominant language (German). This combination of structural and functional imaging therefore highlights the contribution of the right posterior paravermis to the control of verbal interference. We suggest that the importance of this region for language processing has previously been missed because most fMRI studies limit the field of view to increase sensitivity, with the lower part of the cerebellum being the region most likely to be excluded.

  19. Neural basis of semantic and syntactic interference in sentence comprehension.

    Science.gov (United States)

    Glaser, Yi G; Martin, Randi C; Van Dyke, Julie A; Hamilton, A Cris; Tan, Yingying

    2013-09-01

    According to the cue-based parsing approach (Lewis, Vasishth, & Van Dyke, 2006), sentence comprehension difficulty derives from interference from material that partially matches syntactic and semantic retrieval cues. In a 2 (low vs. high semantic interference)×2 (low vs. high syntactic interference) fMRI study, greater activation was observed in left BA44/45 for high versus low syntactic interference conditions following sentences and in left BA45/47 for high versus low semantic interference conditions following comprehension questions. A conjunction analysis showed BA45 associated with both types of interference, while BA47 was associated with only semantic interference. Greater activation was also observed in the left STG in the high interference conditions. Importantly, the results for the LIFG could not be attributed to greater working memory capacity demands for high interference conditions. The results favor a fractionation of the LIFG wherein BA45 is associated with post-retrieval selection and BA47 with controlled retrieval of semantic information.

  20. 47 CFR 101.509 - Interference protection criteria.

    Science.gov (United States)

    2010-10-01

    ..., and radiation pattern of the transmitting and receiving antennas. Licensees are expected to cooperate fully in attempting to resolve problems of potential interference before bringing the matter to...

  1. On the Beamforming Design for Efficient Interference Alignment

    CERN Document Server

    Choi, Sang Won; Chung, Sae-Young

    2009-01-01

    An efficient interference alignment (IA) scheme is developed for $K$-user single-input single-output frequency selective fading interference channels. The main idea is to steer the transmit beamforming matrices such that at each receiver the subspace dimensions occupied by interference-free desired streams are asymptotically the same as those occupied by all interferences. Our proposed scheme achieves a higher multiplexing gain at any given number of channel realizations in comparison with the original IA scheme, which is known to achieve the optimal multiplexing gain asymptotically.

  2. 47 CFR 101.105 - Interference protection criteria.

    Science.gov (United States)

    2010-10-01

    ... radio that is modulated by a standard, television (visual) signal, the allowable interference level per... region consisting of the following states: Wyoming, Colorado, New Mexico, Utah, Arizona, Nevada,...

  3. Two-photon Interference with Non-identical Photons

    CERN Document Server

    Liu, Jianbin; Zheng, Huaibin; Chen, Hui; Li, Fu-Li; Xu, Zhuo

    2014-01-01

    The indistinguishability of non-identical photons is dependent on detection system in quantum physics. If two photons with different wavelengths are indistinguishable for a detection system, there can be two-photon interference when these two photons are incident to two input ports of a Hong-Ou-Mandel interferometer, respectively. The reason why two-photon interference phenomena are different for classical and nonclassical light is not due to interference, but due to the properties of light and detection system. These conclusions are helpful to understand the physics and applications of two-photon interference.

  4. Adaptive cancellation of Es layer interference using auxiliary horizontal antennas

    Institute of Scientific and Technical Information of China (English)

    Zhao Long; Zhang Ning

    2006-01-01

    Based on a dual-polarization high-frequency wave radar system, an adaptive system using horizontal antennas for the suppression of the Es layer interference (ELI) is described. The data received from the horizontal antennas were correlated with the data received from the Vertically Polarized Antennas (VPAs) to estimate and cancel the interference adaptively in the VPAs. Suppressing the interference after each coherent integration time interval, about 25 dB signal-to-interference ratio is expected with the experimentally derived data.

  5. An Anti-Interference Coding in UWB-OFDM Communications

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-bing; CAO Shi-ke; ZHANG Li-jun

    2005-01-01

    An anti-interference orthogonal coding is introduced based on Hadamard code and Orthogonal Frequency-Division Multiplexing (OFDM), in which all sub-channels of Ultra-WideBand (UWB) system are divided into M sub-bands and the power of the every transmitted symbol spreads over each of the sub-bands rather than one sub-band. The complete mathematical analytical relation between encoding and decoding is present and the robustness of the system to interference is examined. When some sub-channels are affected by interference or jamming, the system could regenerate the symbol from others. Simulation results show that the Anti-Interference UWB-OFDM (AI-OFDM) system has evident advantages over conventional UWB-OFDM systems as well as the Interference Suppressing UWB-OFDM (IS-OFDM) in Bit Error Rate (BER) thanks to its robustness to interference. In the case of bad interference, the AI-OFDM system could work up to snuff without any anti-interference step, but the conventional UWB-OFDM system couldn't. Compared with the IS-OFDM system, the AI-OFDM system improves the performance about 5 dB in Signal-to-Interference Ratio (SIR) and the order of 1~2 in BER.

  6. Cognitive interference modeling with applications in power and admission control

    KAUST Repository

    Mahmood, Nurul Huda

    2012-10-01

    One of the key design challenges in a cognitive radio network is controlling the interference generated at coexisting primary receivers. In order to design efficient cognitive radio systems and to minimize their unwanted consequences, it is therefore necessary to effectively control the secondary interference at the primary receivers. In this paper, a generalized framework for the interference analysis of a cognitive radio network where the different secondary transmitters may transmit with different powers and transmission probabilities, is presented and various applications of this interference model are demonstrated. The findings of the analytical performance analyses are confirmed through selected computer-based Monte-Carlo simulations. © 2012 IEEE.

  7. Carbon cycle and climate commitments from early human interference

    Science.gov (United States)

    Zickfeld, K.; Solomon, S.

    2015-12-01

    According to the early anthropogenic hypothesis proposed by Ruddiman (2003), human influence on Earth's climate began several thousand years before the beginning of the industrial era. Agriculture and deforestation starting around 8000 years before present (BP) and slowly increasing over the Holocene, would have led to an increase in atmospheric methane (CH4) and carbon dioxide (CO2) concentration, preventing a natural cooling of Earth's climate. Here, the emphasis is not on testing Ruddiman's hypothesis, but rather on exploring the carbon cycle and climate commitment from potential early CH4 and CO2 emissions. In contrast to modern greenhouse gas emissions, early emissions occurred over millennia, allowing the climate system to come to near-equilibrium with the applied forcing. We perform two transient Holocene simulations with an Earth system model of intermediate complexity - the University of Victoria Earth System Climate Model (UVic ESCM). The first simulation is a standard transient Holocene simulation, forced with reconstructed changes in CO2 and CH4 concentrations and orbital and volcanic forcing. The second simulation is forced with CO2 and CH4 concentrations corrected for the net anthropogenic contribution postulated by Ruddiman (2007), with other forcings evolving as in the standard simulation. The difference in diagnosed emissions between the two simulations allows us to determine the anthropogenic emissions. After year 1850, anthropogenic CO2 and CH4 emissions are set to zero and the simulations continued for several hundred years. In this paper, we analyze the carbon cycle and climate response to the applied forcings, and quantify the resulting (post 1850) commitment from early anthropogenic interference.

  8. On the Degrees of Freedom Achievable Through Interference Alignment in a MIMO Interference Channel

    CERN Document Server

    Razaviyayn, Meisam; Luo, Zhi-Quan

    2011-01-01

    Consider a K-user flat fading MIMO interference channel where the k-th transmitter (or receiver) is equipped with M_k (respectively N_k) antennas. If a large number of statistically independent channel extensions are allowed either across time or frequency, the recent work [1] suggests that the total achievable degrees of freedom (DoF) can be maximized via interference alignment, resulting in a total DoF that grows linearly with K even if M_k and N_k are bounded. In this work we consider the case where no channel extension is allowed, and establish a general condition that must be satisfied by any degrees of freedom tuple (d_1, d2, ..., d_K) achievable through linear interference alignment. For a symmetric system with M_k = M, N_k = N, d_k = d for all k, this condition implies that the total achievable DoF cannot grow linearly with K, and is in fact no more than K(M + N)=(K + 1). We also show that this bound is tight when the number of antennas at each transceiver is divisible by the number of data streams.

  9. Interference Alignment and Neutralization in a Cognitive 3-User MAC-Interference Channel: Degrees of Freedom

    CERN Document Server

    Chaaban, Anas

    2011-01-01

    A network consisting of a point-to-point (P2P) link and a multiple access channel (MAC) sharing the same medium is considered. The resulting interference network, with three transmitters and two receivers is studied from degrees of freedom (DoF) perspective, with and without cognition. Several cognition variants are examined. Namely, the setup is studied with (1) no cognitive transmitters, (2) a cognitive P2P transmitter, (3) one cognitive MAC transmitter, and (4) with two cognitive MAC transmitters. It is shown that having a cognitive P2P transmitter does not bring any DoF gain to the network. This is obtained by showing that the DoF of the two former cases (1) and (2) is 1. However, it is shown that a cognitive MAC transmitter is more beneficial since the latter two cases (3) and (4) have 3/2 DoF. The achievability of 3/2 DoF is guaranteed by using a combination of interference neutralization and interference alignment.

  10. Crystallized Rates Region of the Interference Channel via Correlated Equilibrium with Interference as Noise

    CERN Document Server

    Charafeddine, Mohamad; Paulraj, Arogyaswami; Cioffi, John

    2010-01-01

    Treating the interference as noise in the n-user interference channel, the paper describes a novel approach to the rates region, composed by the time-sharing convex hull of 2^n-1 corner points achieved through On/Off binary power control. The resulting rates region is denoted crystallized rates region. By treating the interference as noise, the n-user rates region frontiers has been found in the literature to be the convex hull of n hyper-surfaces. The rates region bounded by these hyper-surfaces is not necessarily convex, and thereby a convex hull operation is imposed through the strategy of time-sharing. This paper simplifies this rates region in the n-dimensional space by having only an On/Off binary power control. This consequently leads to 2^n-1 corner points situated within the rates region. A time-sharing convex hull is imposed onto those corner points, forming the crystallized rates region. The paper focuses on game theoretic concepts to achieve that crystallized convex hull via correlated equilibrium...

  11. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful...

  12. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the histor...

  13. Clouds in Planetary Atmospheres

    Science.gov (United States)

    West, R.; Murdin, P.

    2000-11-01

    What are clouds? The answer to that question is both obvious and subtle. In the terrestrial atmosphere clouds are familiar as vast collections of small water drops or ice crystals suspended in the air. In the atmospheres of Venus, Mars, Jupiter, Saturn, Saturn's moon Titan, Uranus, Neptune, and possibly Pluto, they are composed of several other substances including sulfuric acid, ammonia, hydroge...

  14. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    Energy Technology Data Exchange (ETDEWEB)

    Broglia, M.F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Suarez, S.; Soldera, F.; Mücklich, F. [Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Barbero, C.A.; Bellingeri, R.; Alustiza, F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Acevedo, D., E-mail: dacevedo@exa.unrc.edu.ar [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina)

    2014-05-01

    Highlights: • We describe the first use of Direct Laser Interference Patterning on PS at 355 nm. . • The structured areas of regular lines are produced in several square millimeters. • The method, Direct Laser Interference Patterning (DLIP) uses a single laser pulse. • DLIP is applied at room temperature and atmospheric pressure. • DLIP is easier to use than other lithographic techniques. • The topography contrasts with the usual Polystyrene ablation at lower wavelengths. - Abstract: The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  15. Interference patterns and extinction ratio of the diatom Coscinodiscus granii

    DEFF Research Database (Denmark)

    Maibohm, Christian; Friis, Søren Michael Mørk; Ellegaard, M.;

    2015-01-01

    We report experimental and theoretical verification of the nature and position of multiple interference points of visible light transmitted through the valve of the centric diatom species Coscinodiscus granii. Furthermore, by coupling the transmitted light into an optical fiber and moving...... the diatom valve between constructive and destructive interference points, an extinction ratio of 20 dB is shown...

  16. Base band data for testing interference mitigation algorithms

    NARCIS (Netherlands)

    Bell, JF; Hall, PJ; Wilson, WE; Sault, RJ; Smegal, RJ; Smith, MR; van Straten, W; Kesteven, MJ; Ferris, RH; Briggs, FH; Carrad, GJ; Sinclair, MW; Gough, RG; Sarkissian, JM; Bunton, JD; Bailes, M

    2001-01-01

    Digital signal processing is one of many valuable tools for suppressing unwanted signals or interference. Building hardware processing engines seems to be the way to best implement some classes of interference suppression but is, unfortunately, expensive and time-consuming, especially if several mit

  17. Confidence set interference with a prior quadratic bound. [in geophysics

    Science.gov (United States)

    Backus, George E.

    1989-01-01

    Neyman's (1937) theory of confidence sets is developed as a replacement for Bayesian interference (BI) and stochastic inversion (SI) when the prior information is a hard quadratic bound. It is recommended that BI and SI be replaced by confidence set interference (CSI) only in certain circumstances. The geomagnetic problem is used to illustrate the general theory of CSI.

  18. 47 CFR 80.92 - Prevention of interference.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Prevention of interference. 80.92 Section 80.92... MARITIME SERVICES Operating Requirements and Procedures Operating Procedures-General § 80.92 Prevention of...-communication causes interference to a communication which is already in progress, the interfering station...

  19. Ensuring Secure Non-interference of Programs by Game Semantics

    DEFF Research Database (Denmark)

    Dimovski, Aleksandar

    Non-interference is a security property which states that improper information leakages due to direct and indirect flows have not occurred through executing programs. In this paper we investigate a game semantics based formulation of non-interference that allows to perform a security analysis...

  20. 47 CFR 15.711 - Interference avoidance mechanisms.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Interference avoidance mechanisms. 15.711... Television Band Devices § 15.711 Interference avoidance mechanisms. (a) Except as provided in § 15.717... mechanism described in paragraph (b) of this section or spectrum sensing described in paragraph (c) of...

  1. Direct laser interference ablating nanostructures on organic crystals

    NARCIS (Netherlands)

    Fang, Hong-Hua; Ding, Ran; Lu, Shi-Yang; Wang, Lei; Feng, Jing; Chen, Qi-Dai; Sun, Hong-Bo; Fang, Honghua

    2012-01-01

    Two-beam interference ablation of 1,4-Bis(4-methylstyryl) benzene organic crystal by short laser pulses (10 ns, 355 nm) is presented. The influence of laser fluence, interference period, and pulse number on the morphology have been studied. The morphology is closely associated with the molecular int

  2. Transparency induced by two photon interference in a beam splitter

    Institute of Scientific and Technical Information of China (English)

    Wang Kai-Ge; Yang Guo-Jian

    2004-01-01

    We propose a special two-photon state which is completely transparent in a 50/50 beam splitter. This effect is caused by the destructive two-photon interference and shows the signature of photon entanglement. We find that the symmetry of the two-photon spectrum plays the key role for the properties of two-photon interference.

  3. Interference Effects in Strong-Field Dissociative Ionization

    DEFF Research Database (Denmark)

    Yue, Lun; Madsen, Lars Bojer

    2015-01-01

    with simple energy conservation arguments. We explain the structures as interferences between wave packets released during different optical cycles, and during the same optical cycle, respectively. Both inter- and intracycle interference structures are clearly visible in the joint energy spectra. The shapes...

  4. Fraunhofer regime of operation for superconducting quantum interference filters

    DEFF Research Database (Denmark)

    Shadrin, A.V.; Constantinian, K.Y.; Ovsyannikov, G.A.;

    2008-01-01

    Series arrays of superconducting quantum interference devices (SQUIDs) with incommensurate loop areas, so-called superconducting quantum interference filters (SQIFs), are investigated in the kilohertz and the gigahertz frequency range. In SQIFs made of high-T-c bicrystal junctions the flux-to-vol...

  5. Interference-Cancellation Scheme for Multilayer Cellular Systems

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Yue Zhang; LiKe Huang

    2015-01-01

    A 5G network must be heterogeneous and support the co⁃existence of multilayer cells, multiple standards, and multiple applica⁃tion systems. This greatly improves link performance and increases link capacity. A network with co⁃existing macro and pico cells can alleviate traffic congestion caused by multicast or unicast subscribers, help satisfy huge traffic demands, and further extend converge. In order to practically implement advanced 5G technology, a number of technical problems have to be solved, one of which is inter⁃cell interference. A method called Almost Blank Subframe (ABS) has been proposed to mitigate interference;howev⁃er, the reference signal in ABS still causes interference. This paper describes how interference can be cancelled by using the in⁃formation in the ABS. First, the interference⁃signal model, which takes into account channel effect, time and frequency error, is presented. Then, an interference⁃cancellation scheme based on this model is studied. The timing and carrier frequency offset of the interference signal is compensated. Afterwards, the reference signal of the interfering cell is generated locally and the channel response is estimated using channel statistics. Then, the interference signal is reconstructed according to previous estimation of channel, timing, and carrier frequency offset. The interference is mitigated by subtracting the estimated interference signal. Com⁃puter simulation shows that this interference⁃cancellation algorithm significantly improves performance under different channel conditions.

  6. Interference of electronic apex locators with implantable cardioverter defibrillators

    NARCIS (Netherlands)

    Idzahi, K.; de Cock, C.C.; Shemesh, H.; Brand, H.S.

    2014-01-01

    Introduction The purpose of this in vitro study was to evaluate the potential electromagnetic interference of electronic apex locators (EALs) on implantable cardioverter defibrillators (ICDs). Methods Four different EALs were tested for their ability to interfere with the correct function of 3 diffe

  7. Quantum Interference and Entanglement Induced by Multiple Scattering of Light

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Mortensen, Asger; Lodahl, Peter

    2010-01-01

    We report on the effects of quantum interference induced by the transmission of an arbitrary number of optical quantum states through a multiple-scattering medium. We identify the role of quantum interference on the photon correlations and the degree of continuous variable entanglement between tw...

  8. Interference impacts working memory in mild cognitive impairment

    Directory of Open Access Journals (Sweden)

    Sara Aurtenetxe

    2016-10-01

    Full Text Available Mild cognitive impairment (MCI is considered a transitional stage between healthy aging and dementia, specifically Alzheimer’s disease (AD. The most common cognitive impairment of MCI includes episodic memory loss and difficulties in working memory (WM. Interference can deplete WM, and an optimal WM performance requires an effective control of attentional resources between the memoranda and the incoming stimuli. Difficulties in handling interference lead to forgetting. However, the interplay between interference and WM in MCI is not well understood and needs further investigation. The current study investigated the effect of interference during a WM task in 20 MCIs and 20 healthy elder volunteers. Participants performed a delayed match-to-sample paradigm which consisted in two interference conditions, distraction and interruption, and one control condition without any interference. Results evidenced a disproportionate impact of interference on the WM performance of MCIs, mainly in the presence of interruption. These findings demonstrate that interference, and more precisely interruption, is an important proxy for memory-related deficits in MCI. Thus the current findings reveal novel evidence regarding the causes of WM forgetting in MCI patients, associated with difficulties in the mechanisms of attentional control.

  9. Interference Impacts Working Memory in Mild Cognitive Impairment

    Science.gov (United States)

    Aurtenetxe, Sara; García-Pacios, Javier; del Río, David; López, María E.; Pineda-Pardo, José A.; Marcos, Alberto; Delgado Losada, Maria L.; López-Frutos, José M.; Maestú, Fernando

    2016-01-01

    Mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia, specifically Alzheimer's disease (AD). The most common cognitive impairment of MCI includes episodic memory loss and difficulties in working memory (WM). Interference can deplete WM, and an optimal WM performance requires an effective control of attentional resources between the memoranda and the incoming stimuli. Difficulties in handling interference lead to forgetting. However, the interplay between interference and WM in MCI is not well-understood and needs further investigation. The current study investigated the effect of interference during a WM task in 20 MCIs and 20 healthy elder volunteers. Participants performed a delayed match-to-sample paradigm which consisted in two interference conditions, distraction and interruption, and one control condition without any interference. Results evidenced a disproportionate impact of interference on the WM performance of MCIs, mainly in the presence of interruption. These findings demonstrate that interference, and more precisely interruption, is an important proxy for memory-related deficits in MCI. Thus, the current findings reveal novel evidence regarding the causes of WM forgetting in MCI patients, associated with difficulties in the mechanisms of attentional control. PMID:27790082

  10. Interference patterns and extinction ratio of the diatom Coscinodiscus granii

    DEFF Research Database (Denmark)

    Maibohm, Christian; Friis, Søren Michael Mørk; Ellegaard, M.;

    2015-01-01

    We report experimental and theoretical verification of the nature and position of multiple interference points of visible light transmitted through the valve of the centric diatom species Coscinodiscus granii. Furthermore, by coupling the transmitted light into an optical fiber and moving the dia...... the diatom valve between constructive and destructive interference points, an extinction ratio of 20 dB is shown...

  11. Quantum interference and diffraction of parametric down-converted biphotons

    Indian Academy of Sciences (India)

    Ryosuke Shimizu; Keiichi Edamatsu; Tadashi Itoh

    2002-08-01

    We present two-photon diffraction and interference experiments utilizing parametric down-converted photon pairs (biphotons) and a transmission grating. The biphoton exhibits a diffraction-interference pattern equivalent to an effective single particle with half wavelength of the constituent photons.

  12. Interference Alignment and Fairness Algorithms for MIMO Cognitive Radio Systems

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-01-01

    Full Text Available Interference alignment (IA is an effective technique to eliminate the interference among wireless nodes. In a multiinput multi-output (MIMO cognitive radio system, multiple secondary users can coexist with the primary user without generating any interference by using the IA technology. However, few works have considered the fairness of secondary users. In this paper, not only is the interference eliminated by IA, but also the fairness of secondary users is considered by two kinds of algorithms. Without losing generality, one primary user and K secondary users are considered in the network. Assuming perfect channel knowledge at the primary user, the interference from secondary users to the primary user is aligned into the unused spatial dimension which is obtained by water-filling among primary user. Also, the interference between secondary users can be eliminated by a modified maximum signal-to-interference-plus-noise algorithm using channel reciprocity. In addition, two kinds of fairness algorithms, max-min fairness and proportional fairness, among secondary users are proposed. Simulation results show the effectiveness of the proposed algorithms in terms of suppressed interference and fairness of secondary nodes. What is more, the performances of the two fairness algorithms are compared.

  13. Optical interference coatings for optics and photonics [Invited].

    Science.gov (United States)

    Lee, Cheng-Chung

    2013-01-01

    Optical interference coatings play as an important role in the progress in optics and photonics. In this article we give a minireview of the evolution of optical interference coatings from the theory, the design, to the manufacture. Some interesting but challenging topics for the future are also discussed.

  14. Role interference and subjective well-being among expatriate families

    NARCIS (Netherlands)

    Van der Zee, KI; Salome, E

    2005-01-01

    The present study examined the relation of demands and social support, and positive and negative Work-Home (WHI) and Home-Work interference (HWI) with the subjective well-being of expatriates. Moreover, we were also interested in crossover effects of expatriate interference to the subjective wellbei

  15. Review Results on Wing-Body Interference

    Directory of Open Access Journals (Sweden)

    Frolov Vladimir

    2016-01-01

    Full Text Available The paper presents an overview of results for wing-body interference, obtained by the author for varied wing-body combinations. The lift-curve slopes of the wing-body combinations are considered. In this paper a discrete vortices method (DVM and 2D potential model for cross-flow around fuselage are used. The circular and elliptical cross-sections of the fuselage and flat wings of various forms are considered. Calculations showed that the value of the lift-curve slopes of the wing-body combinations may exceed the same value for an isolated wing. This result confirms an experimental data obtained by other authors earlier. Within a framework of the used mathematical models the investigations to optimize the wing-body combination were carried. The present results of the optimization problem for the wing-body combination allowed to select the optimal geometric characteristics for configuration to maximize the values of the lift-curve slopes of the wing-body combination. It was revealed that maximums of the lift-curve slopes for the optimal mid-wing configuration with elliptical cross-section body had a sufficiently large relative width of the body (more than 30% of the span wing.

  16. Differential interference contrast microscopy using Savart plates

    Science.gov (United States)

    Trịnh, Hưng-Xuân; Lin, Shyh-Tsong; Chen, Liang-Chia; Yeh, Sheng-Lih; Chen, Chin-Sheng

    2017-04-01

    A new differential interference contrast microscopy (DICM), which uses Savart prisms as a shearing plate and a phase-shifting device, is proposed. The system consists of a phase-shifting module (PSM) and a DICM module (DICMM). The PSM has two Savart prisms: the first prism separates the incident beam into two parallel beams, and the second prism recombines these two beams. The optical path difference (OPD) of the two beams, which is represented by a biased OPD, can be adjusted by rotating the angle of the normal surface of the second prism. In the DICMM, the other Savart prism is used to replace the Nomarski prism (NP) in conventional DICM. It combines with an afocal microscopic system (AMS) to produce a Savart-DICM system, which is able to perform a phase-shifting technique by changing the biased OPD to produce a phase shift of π/2 for each step. This paper describes the configuration and measurement theory of the microscope. The experimental results confirm the validity and capability of the proposed microscope.

  17. Interference with the patient-physician relationship

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2012-11-01

    Full Text Available No abstract available. Article truncated at 150 words. “Life is like a boomerang. Our thoughts, deeds and words return to us sooner or later, with astounding accuracy.”-Brant M. Bright, former project leader with IBM A recent sounding board in the New England Journal of Medicine discussed legislative interference with the patient-physician relationship (1. The authors, the executive staff leadership of the American Academy of Family Physicians, the American Academy of Pediatrics, the American College of Obstetricians and Gynecologists, the American College of Physicians, and the American College of Surgeons believe that legislators should abide by principles that put patients’ best interests first. Critical to achieving this goal is respect for the importance of scientific evidence, patient autonomy, and the patient-physician relationship. According to the authors, lawmakers are increasingly intruding into the realm of medical practice, often to satisfy political agendas without regard to established, evidence-based guidelines for care. The article goes on to cite examples including: The Florida ….

  18. Interference and interactions in open quantum dots

    CERN Document Server

    Bird, J P; Ferry, D K; Moura, A P S; Lai, Y C; Indlekofer, K M

    2003-01-01

    In this report, we review the results of our joint experimental and theoretical studies of electron-interference, and interaction, phenomena in open electron cavities known as quantum dots. The transport through these structures is shown to be heavily influenced by the remnants of their discrete density of states, elements of which remain resolved in spite of the strong coupling that exists between the cavity and its reservoirs. The experimental signatures of this density of states are discussed at length in this report, and are shown to be related to characteristic wavefunction scarring, involving a small number of classical orbits. A semiclassical analysis of this behaviour shows it to be related to the effect of dynamical tunnelling, in which electrons are injected into the dot tunnel through classically forbidden regions of phase space, to access isolated regular orbits. The dynamical tunnelling gives rise to the formation of long-lived quasi-bound states in the open dots, and the many-body implications a...

  19. p53 gene therapy using RNA interference.

    Science.gov (United States)

    Berindan-Neagoe, I; Balacescu, O; Burz, C; Braicu, C; Balacescu, L; Tudoran, O; Cristea, V; Irimie, A

    2009-09-01

    p53 gene, discovered almost 35 years ago, keeps the main role in cell cycle control, apoptosis pathways and transcription. p53 gene is found mutated in more than 50% of all human cancers in different locations. Many structures from viral to non viral were designed to incorporate and deliver in appropriate conditions forms of p53 gene or its transcripts, systemically to target tumor cells and to eliminate them through apoptosis or to restore the normal tumor suppressor gene role. Each delivery system presents advantages and low performance in relation to immune system recognition and acceptance. One of the major discoveries in the last years, silencing of RNA, represents a powerful tool for inhibiting post transcriptional control of gene expression. According to several studies, the RNA silencing technology for p53 transcripts together with other carriers or transporters at nano level can be used for creating new therapeutic models. RNA interference for p53 uses different double-stranded (ds) molecules like short interfering (si) RNA and, despite the difficulty of introducing them into mammalian cells due to immune system response, it can be exploited in cancer therapy.

  20. Fiber Optic Pressure Sensor using Multimode Interference

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Perez, V I; Sanchez-Mondragon, J J [INAOE, Apartado Postal 51 y 216, Puebla 72000 (Mexico); Basurto-Pensado, M A [CIICAp, Universidad Autonoma del Estado de Morelos (Mexico); LiKamWa, P [CREOL, University of Central Florida, Orlando, FL 32816 (United States); May-Arrioja, D A, E-mail: iruiz@inaoep.mx, E-mail: mbasurto@uaem.mx, E-mail: delta_dirac@hotmail.com, E-mail: daniel_may_arrioja@hotmail.com [UAT Reynosa Rodhe, Universidad Autonoma de Tamaulipas (Mexico)

    2011-01-01

    Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 {mu}V/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal.

  1. Environmental Factors that Interfere in the Germination

    Directory of Open Access Journals (Sweden)

    Lisiane de Souza

    2014-12-01

    Full Text Available This paper refers to the application of experiments with sixth graders of elementary school, aiming motivation, skills development focused on observation, interpersonal relationships in teams, related to the various forms of language skills, as well to identify and resume misconceptions about the external (environmental factors required for seed germination, in order that the contents developed this year refer to the study of the earth, soil, water and air, among others, and that many students do not understand all the concepts and the importance of these factors for the existence of living beings. The experiments were organized in two stages, first to observe the influence of soil and another moment to observe the interference of water, air and light. The temperature impractical activities were conducted, however, during the observation period (three weeks experiments remained in a controlled environment in the science laboratory. For the experiments we used materials easily found in commerce, some recycled; students were organized into six teams, which improved the data collection, the maintenance of the experiments, the calculations of the percentages, and the producing of report. Many of these contents had not yet been studied in other disciplines, but were developed in the discipline of science, respecting prior knowledge and cognitive abilities. The use of experiments was effective for the construction of new knowledge and to develop skills necessary to start the search.

  2. Separating cyclostationary signals from spectrally overlapping interference

    Institute of Scientific and Technical Information of China (English)

    GUO Jie; LIU Yun; YE Zhi-hui; SONG Tie-cheng; SHEN Lian-feng

    2006-01-01

    This paper studies an algorithm about separating spectmlly overlapping signals using the cyclostationary properties of signals.On the basis of direct sequence spread system (DSSS),frequency shift filter is added into the receiver of the communication system.Although the structure of frequency shift filter is more complicated than the time-domain filter,it uses both time correlations and frequency spectrum correlations so it can achieve better performances on separating the overlapping signals.After the analysis of cyclostationary characteristic and frequency spectrum correlation,the structure of the frequency shift filter can be gained.Then,a self-adaptive algorithm is utilized for the purpose of achieving optimum multidimensional tap weights of frequency shift components.The simulation results indicate that this method can efficiently separate overlapping signals,and its error rate is lower than the time-domain filter or DSSS system by two orders of magnitude on the condition that high-power interference is added into the system.

  3. Interference enhanced thermoelectricity in quinoid type structures.

    Science.gov (United States)

    Strange, M; Seldenthuis, J S; Verzijl, C J O; Thijssen, J M; Solomon, G C

    2015-02-28

    Quantum interference (QI) effects in molecular junctions may be used to obtain large thermoelectric responses. We study the electrical conductance G and the thermoelectric response of a series of molecules featuring a quinoid core using density functional theory, as well as a semi-empirical interacting model Hamiltonian describing the π-system of the molecule which we treat in the GW approximation. Molecules with a quinoid type structure are shown to have two distinct destructive QI features close to the frontier orbital energies. These manifest themselves as two dips in the transmission, that remain separated, even when either electron donating or withdrawing side groups are added. We find that the position of the dips in the transmission and the frontier molecular levels can be chemically controlled by varying the electron donating or withdrawing character of the side groups as well as the conjugation length inside the molecule. This feature results in a very high thermoelectric power factor S(2)G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices.

  4. Instantaneous Relaying: Optimal Strategies and Interference Neutralization

    CERN Document Server

    Ho, Zuleita

    2012-01-01

    In a multi-user wireless network equipped with multiple relay nodes, some relays are more intelligent than other relay nodes. The intelligent relays are able to gather channel state information, perform linear processing and forward signals whereas the dumb relays is only able to serve as amplifiers. As the dumb relays are oblivious to the source and destination nodes, the wireless network can be modeled as a relay network with *smart instantaneous relay* only: the signals of source-destination arrive at the same time as source-relay-destination. Recently, instantaneous relaying is shown to improve the degrees-of-freedom of the network as compared to classical cut-set bound. In this paper, we study an achievable rate region and its boundary of the instantaneous interference relay channel in the scenario of (a) uninformed non-cooperative source-destination nodes (source and destination nodes are not aware of the existence of the relay and are non-cooperative) and (b) informed and cooperative source-destination...

  5. RNA interference and Register Machines (extended abstract

    Directory of Open Access Journals (Sweden)

    Masahiro Hamano

    2012-11-01

    Full Text Available RNA interference (RNAi is a mechanism whereby small RNAs (siRNAs directly control gene expression without assistance from proteins. This mechanism consists of interactions between RNAs and small RNAs both of which may be single or double stranded. The target of the mechanism is mRNA to be degraded or aberrated, while the initiator is double stranded RNA (dsRNA to be cleaved into siRNAs. Observing the digital nature of RNAi, we represent RNAi as a Minsky register machine such that (i The two registers hold single and double stranded RNAs respectively, and (ii Machine's instructions are interpreted by interactions of enzyme (Dicer, siRNA (with RISC com- plex and polymerization (RdRp to the appropriate registers. Interpreting RNAi as a computational structure, we can investigate the computational meaning of RNAi, especially its complexity. Initially, the machine is configured as a Chemical Ground Form (CGF, which generates incorrect jumps. To remedy this problem, the system is remodeled as recursive RNAi, in which siRNA targets not only mRNA but also the machine instructional analogues of Dicer and RISC. Finally, probabilistic termination is investigated in the recursive RNAi system.

  6. Quantum Interference and Selectivity through Biological Ion Channels

    Science.gov (United States)

    Salari, Vahid; Naeij, Hamidreza; Shafiee, Afshin

    2017-01-01

    The mechanism of selectivity in ion channels is still an open question in biology for more than half a century. Here, we suggest that quantum interference can be a solution to explain the selectivity mechanism in ion channels since interference happens between similar ions through the same size of ion channels. In this paper, we simulate two neighboring ion channels on a cell membrane with the famous double-slit experiment in physics to investigate whether there is any possibility of matter-wave interference of ions via movement through ion channels. Our obtained decoherence timescales indicate that the quantum states of ions can only survive for short times, i.e. ≈100 picoseconds in each channel and ≈17–53 picoseconds outside the channels, giving the result that the quantum interference of ions seems unlikely due to environmental decoherence. However, we discuss our results and raise few points, which increase the possibility of interference. PMID:28134331

  7. High-Q Bandpass Comb Filter for Mains Interference Extraction

    Directory of Open Access Journals (Sweden)

    Neycheva T.

    2009-12-01

    Full Text Available This paper presents a simple digital high-Q bandpass comb filter for power-line (PL or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.

  8. Interference Cancellation Using Space-Time Processing and Precoding Design

    CERN Document Server

    Li, Feng

    2013-01-01

    Interference Cancellation Using Space-Time Processing and Precoding Design introduces original design methods to achieve interference cancellation, low-complexity decoding and full diversity for a series of multi-user systems. In multi-user environments, co-channel interference will diminish the performance of wireless communications systems. In this book, we investigate how to design robust space-time codes and pre-coders to suppress the co-channel interference when multiple antennas are available.   This book offers a valuable reference work for graduate students, academic researchers and engineers who are interested in interference cancellation in wireless communications. Rigorous performance analysis and various simulation illustrations are included for each design method.   Dr. Feng Li is a scientific researcher at Cornell University.

  9. Electromagnetic interference in electrical systems of motor vehicles

    Science.gov (United States)

    Dziubiński, M.; Drozd, A.; Adamiec, M.; Siemionek, E.

    2016-09-01

    Electronic ignition system affects the electronic equipment of the vehicle by electric and magnetic fields. The measurement of radio electromagnetic interference originating from the ignition system affecting the audiovisual test bench was carried out with a variable speed of the ignition system. The paper presents measurements of radio electromagnetic interference in automobiles. In order to determine the level of electromagnetic interference, the audiovisual test bench was equipped with a set of meters for power consumption and assessment of the level of electromagnetic interference. Measurements of the electromagnetic interference level within the audiovisual system were performed on an experimental test bench consisting of the ignition system, starting system and charging system with an alternator and regulator.

  10. Proposal of interference reduction routing for ad-hoc networks

    Directory of Open Access Journals (Sweden)

    Katsuhiro Naito

    2010-10-01

    Full Text Available In this paper, we propose an interference reduction routing protocol for ad-hoc networks. The interference is one of the degradation factors in wireless communications. In the ad-hoc network, some nodes communicate simultaneously. Therefore, these communications cause interference each other, and some packets are corrupted due to interference from another node. In the proposed protocol, each node estimates required transmission power according to hello messages. Therefore, the node can transmit a data packet with minimum required transmission power. Consequently, the interference against neighbor nodes can be reduced. From simulation results, we can find that the proposed protocol can reduce the number of control messages and can improve the throughput performance.

  11. Ruling Out Multi-Order Interference in Quantum Mechanics

    CERN Document Server

    Sinha, Urbasi; Jennewein, Thomas; Laflamme, Raymond; Weihs, Gregor

    2010-01-01

    Quantum mechanics and gravitation are two pillars of modern physics. Despite their success in describing the physical world around us, they seem to be incompatible theories. There are suggestions that one of these theories must be generalized to achieve unification. For example, Born's rule, one of the axioms of quantum mechanics could be violated. Born's rule predicts that quantum interference, as shown by a double slit diffraction experiment, occurs from pairs of paths. A generalized version of quantum mechanics might allow multi-path, i.e. higher order interferences thus leading to a deviation from the theory. We performed a three slit experiment with photons and bounded the magnitude of three path interference to less than 10-2 of the expected two-path interference, thus ruling out third and higher order interference and providing a bound on the accuracy of Born's rule. Our experiment is consistent with the postulate both in semi-classical and quantum regimes.

  12. Modular interference characteristic of two-mode fiber

    Institute of Scientific and Technical Information of China (English)

    Helin Wang; Weihong Bi; Aijun Yang; Feng Liu

    2006-01-01

    The modular interference characteristics of circular-core and elliptical-core two-mode fibers are investigated in theory. The intensity distribution and figure of two-lobe mode patterns are evaluated and simulated quantitatively for different phase difference change between LP01 and LPeven11 mode. The interference mode patters of elliptical-core and circular-core two-mode fibers are compared, the result shows that the two-lobe interference patters of the two-mode fibers generate energy exchange and oscillation, and thedifference is that the interference mode patterns of circular-core two-mode fiber are almost elliptical, while the interference mode pattern of elliptical-core two-mode fiber is approximately circular on condition that proper selection of the ellipticity. Their two-dimensional (2D) profile determines the choice of the core shape of the information pick-up fiber.

  13. Ruling out multi-order interference in quantum mechanics.

    Science.gov (United States)

    Sinha, Urbasi; Couteau, Christophe; Jennewein, Thomas; Laflamme, Raymond; Weihs, Gregor

    2010-07-23

    Quantum mechanics and gravitation are two pillars of modern physics. Despite their success in describing the physical world around us, they seem to be incompatible theories. There are suggestions that one of these theories must be generalized to achieve unification. For example, Born's rule--one of the axioms of quantum mechanics--could be violated. Born's rule predicts that quantum interference, as shown by a double-slit diffraction experiment, occurs from pairs of paths. A generalized version of quantum mechanics might allow multipath (i.e., higher-order) interference, thus leading to a deviation from the theory. We performed a three-slit experiment with photons and bounded the magnitude of three-path interference to less than 10(-2) of the expected two-path interference, thus ruling out third- and higher-order interference and providing a bound on the accuracy of Born's rule. Our experiment is consistent with the postulate both in semiclassical and quantum regimes.

  14. Atmospheric composition change: Ecosystems–Atmosphere interactions

    DEFF Research Database (Denmark)

    Fowler, D.; Pilegaard, Kim; Sutton, M.A.

    2009-01-01

    and techniques in micrometeorology. For some of the compounds there have been paradigm shifts in approach and application of both techniques and assessment. These include flux measurements over marine surfaces and urban areas using micrometeorological methods and the up-scaling of flux measurements using...... in the size range 1 nm–10 μm including organic and inorganic chemical species. The main focus of the review is on the exchange between terrestrial ecosystems, both managed and natural and the atmosphere, although some new developments in ocean–atmosphere exchange are included. The material presented is biased...... towards the last decade, but includes earlier work, where more recent developments are limited or absent. New methodologies and instrumentation have enabled, if not driven technical advances in measurement. These developments have advanced the process understanding and upscaling of fluxes, especially...

  15. Glacial atmospheric phosphorus deposition

    Science.gov (United States)

    Kjær, Helle Astrid; Dallmayr, Remi; Gabrieli, Jacopo; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Svensson, Anders; Vallelonga, Paul

    2016-04-01

    Phosphorus in the atmosphere is poorly studied and thus not much is known about atmospheric phosphorus and phosphate transport and deposition changes over time, though it is well known that phosphorus can be a source of long-range nutrient transport, e.g. Saharan dust transported to the tropical forests of Brazil. In glacial times it has been speculated that transport of phosphorus from exposed shelves would increase the ocean productivity by wash out. However whether the exposed shelf would also increase the atmospheric load to more remote places has not been investigated. Polar ice cores offer a unique opportunity to study the atmospheric transport of aerosols on various timescales, from glacial-interglacial periods to recent anthropogenic influences. We have for the first time determined the atmospheric transport of phosphorus to the Arctic by means of ice core analysis. Both total and dissolved reactive phosphorus were measured to investigate current and past atmospheric transport of phosphorus to the Arctic. Results show that glacial cold stadials had increased atmospheric total phosphorus mass loads of 70 times higher than in the past century, while DRP was only increased by a factor of 14. In the recent period we find evidence of a phosphorus increase over the past 50 yrs in ice cores close to human occupation likely correlated to forest fires. References: Kjær, Helle Astrid, et al. "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores." Environmental science & technology 47.21 (2013): 12325-12332. Kjær, Helle Astrid, et al. "Greenland ice cores constrain glacial atmospheric fluxes of phosphorus." Journal of Geophysical Research: Atmospheres120.20 (2015).

  16. Atmosphere beyond Poetics

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2014-01-01

    . In doing so, analysing the Crystal Palace – recognised as the epitome of controlled immersive experience as well as of atmospheric engineering (Sloterdijk 2008 (2005) – in parallel with other examples and theoretical explorations, will provide a canvas for discerning the means of creation of atmosphere...... Physical Presence in Space.” Oase #91, Building Atmosphere, 21-33 Sloterdijk, Peter. (2005) 2008. “The Crystal Palace.” Translated by Michael Darroch. Public 37: Public?, 12-15. Originally published in Peter Sloterdijk. Im Weltinnenraum des Kapitals: Für eine philoso-phische Theorie der Globalisierung, 265...

  17. Role of RNA interference in plant improvement

    Science.gov (United States)

    Jagtap, Umesh Balkrishna; Gurav, Ranjit Gajanan; Bapat, Vishwas Anant

    2011-06-01

    Research to alter crops for their better performance involving modern technology is underway in numerous plants, and achievements in transgenic plants are impacting crop improvements in unparalleled ways. Striking progress has been made using genetic engineering technology over the past two decades in manipulating genes from diverse and exotic sources, and inserting them into crop plants for inducing desirable characteristics. RNA interference (RNAi) has recently been identified as a natural mechanism for regulation of gene expression in all higher organisms from plants to humans and promises greater accuracy and precision to plant improvement. The expression of any gene can be down-regulated in a highly explicit manner exclusive of affecting the expression of any other gene by using RNAi technologies. Additional research in this field has been focused on a number of other areas including microRNAs, hairpin RNA, and promoter methylation. Manipulating new RNAi pathways, which generate small RNA molecules to amend gene expression in crops, can produce new quality traits and having better potentiality of protection against abiotic and biotic stresses. Nutritional improvement, change in morphology, or enhanced secondary metabolite synthesis are some of the other advantages of RNAi technology. In addition to its roles in regulating gene expression, RNAi is also used as a natural defense mechanism against molecular parasites such as jumping genes and viral genetic elements that affect genome stability. Even though much advancement has been made on the field of RNAi over the preceding few years, the full prospective of RNAi for crop improvement remains to be fully realized. The intricacy of RNAi pathway, the molecular machineries, and how it relates to plant development are still to be explained.

  18. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    Science.gov (United States)

    Lu, Qi; Yu, Jialin; Yang, Xiqiang; Wang, Jiarong; Wang, Lijia; Lin, Yayin; Lin, Lihua

    2010-09-01

    The mucolytic agent ambroxol has been reported to interfere with the formation of Pseudomonas aeruginosa-derived biofilms in addition to reducing alginate production by undefined mechanisms. Since quorum sensing is a key regulator of virulence and biofilm formation, we examined the effects of ambroxol on P. aeruginosa PAO1 wild-type bacterial clearance rates, adhesion profiles and biofilm formation compared with the quorum sensing-deficient, double-mutant strains DeltalasR DeltarhlR and DeltalasI DeltarhlI. Data presented in this report demonstrated that ambroxol treatment reduced survival rates of the double-mutant strains compared with the wild-type strain in a dose-dependent manner even though the double-mutants had increased adhesion in the presence of ambroxol compared with the wild-type strain. The PAO1 wild-type strain produced a significantly thicker biofilm (21.64+/-0.57 microm) compared with the biofilms produced by the DeltalasR DeltarhlR (7.36+/-0.2 microm) and DeltalasI DeltarhlI (6.62+/-0.31 microm) isolates. Ambroxol treatment reduced biofilm thickness, increased areal porosity, and decreased the average diffusion distance and textual entropy of wild-type and double-mutant strains. However, compared with the double-mutant strains, the changes observed for the wild-type strain were more clearly defined. Finally, ambroxol exhibited significant antagonistic quorum-sensing properties, suggesting that it could be adapted for use clinically in the treatment of cystic fibrosis and to reduce biofilm formation and in the colonisation of indwelling devices.

  19. Interference between nanoparticles and metal homeostasis

    Science.gov (United States)

    Petit, A. N.; Aude Garcia, C.; Candéias, S.; Casanova, A.; Catty, P.; Charbonnier, P.; Chevallet, M.; Collin-Faure, V.; Cuillel, M.; Douki, T.; Herlin-Boime, N.; Lelong, C.; Luche, S.; Mintz, E.; Moulis, J. M.; Nivière, V.; Ollagnier de Choudens, S.; Rabilloud, T.; Ravanat, J. L.; Sauvaigo, S.; Carrière, M.; Michaud-Soret, I.

    2011-07-01

    The TiO2 nanoparticles (NPs) are now produced abundantly and widely used in a variety of consumer products. Due to the important increase in the production of TiO2-NPs, potential widespread exposure of humans and environment may occur during both the manufacturing process and final use. Therefore, the potential toxicity of TiO2-NPs on human health and environment has attracted particular attention. Unfortunately, the results of the large number of studies on the toxicity of TiO2-NPs differ significantly, mainly due to an incomplete characterization of the used nanomaterials in terms of size, shape and crystalline structure and to their unknown state of agglomeration/aggregation. The purpose of our project entitled NanoBioMet is to investigate if interferences between nanoparticles and metal homeostasis could be observed and to study the toxicity mechanisms of TiO2-NPs with well-characterized physicochemical parameters, using proteomic and molecular approaches. A perturbation of metal homeostasis will be evaluated upon TiO2-NPs exposure which could generate reactive oxygen species (ROS) production. Moreover, oxidative stress consequences such as DNA damage and lipid peroxidation will be studied. The toxicity of TiO2-NPs of different sizes and crystalline structures will be evaluated both in prokaryotic (E. coli) and eukaryotic cells (A549 human pneumocytes, macrophages, and hepatocytes). First results of the project will be presented concerning the dispersion of TiO2-NPs in bacterial medium, proteomic studies on total extracts of macrophages and genotoxicity on pneumocytes.

  20. Interference between nanoparticles and metal homeostasis

    Energy Technology Data Exchange (ETDEWEB)

    Petit, A N; Catty, P; Charbonnier, P; Cuillel, M; Mintz, E; Moulis, J M; Niviere, V; Choudens, S Ollagnier de [Laboratoire de Chimie et Biologie des Metaux UMR 5249 CEA-CNRS-UJF, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France); Garcia, C Aude; Candeias, S; Chevallet, M; Collin-Faure, V; Lelong, C; Luche, S; Rabilloud, T [Laboratoire de Biochimie et Biophysique des Systemes Integres UMR 5092 CNRS-CEA-UJF, 17 rue des martyrs, 38054 Grenoble Cedex 09 (France); Casanova, A; Herlin-Boime, N [Laboratoire Edifices Nanometriques URA 2453 CEA-CNRS-IRAMIS, 91191 Gif-sur-Yvette (France); Douki, T; Ravanat, J L; Sauvaigo, S, E-mail: isabelle.michaud-soret@cea.fr [Laboratoire Lesions des Acides Nucleiques UMR E3 CEA-UJF, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France)

    2011-07-06

    The TiO{sub 2} nanoparticles (NPs) are now produced abundantly and widely used in a variety of consumer products. Due to the important increase in the production of TiO{sub 2}-NPs, potential widespread exposure of humans and environment may occur during both the manufacturing process and final use. Therefore, the potential toxicity of TiO{sub 2}-NPs on human health and environment has attracted particular attention. Unfortunately, the results of the large number of studies on the toxicity of TiO{sub 2}-NPs differ significantly, mainly due to an incomplete characterization of the used nanomaterials in terms of size, shape and crystalline structure and to their unknown state of agglomeration/aggregation. The purpose of our project entitled NanoBioMet is to investigate if interferences between nanoparticles and metal homeostasis could be observed and to study the toxicity mechanisms of TiO{sub 2}-NPs with well-characterized physicochemical parameters, using proteomic and molecular approaches. A perturbation of metal homeostasis will be evaluated upon TiO{sub 2}-NPs exposure which could generate reactive oxygen species (ROS) production. Moreover, oxidative stress consequences such as DNA damage and lipid peroxidation will be studied. The toxicity of TiO{sub 2}-NPs of different sizes and crystalline structures will be evaluated both in prokaryotic (E. coli) and eukaryotic cells (A549 human pneumocytes, macrophages, and hepatocytes). First results of the project will be presented concerning the dispersion of TiO{sub 2}-NPs in bacterial medium, proteomic studies on total extracts of macrophages and genotoxicity on pneumocytes.

  1. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE approximation and assuming that the magnetic field does not exceed 10^8 G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra.

  2. The invention of atmosphere.

    Science.gov (United States)

    Martin, Craig

    2015-08-01

    The word "atmosphere" was a neologism Willebrord Snellius created for his Latin translation of Simon Stevin's cosmographical writings. Astronomers and mathematical practitioners, such as Snellius and Christoph Scheiner, applying the techniques of Ibn Mu'ādh and Witelo, were the first to use the term in their calculations of the height of vapors that cause twilight. Their understandings of the atmosphere diverged from Aristotelian divisions of the aerial region. From the early years of the seventeenth century, the term was often associated with atomism or corpuscular matter theory. The concept of the atmosphere changed dramatically with the advent of pneumatic experiments in the middle of the seventeenth century. Pierre Gassendi, Walter Charleton, and Robert Boyle transformed the atmosphere of the mathematicians giving it the characteristics of weight, specific gravity, and fluidity, while disputes about its extent and border remained unresolved.

  3. Interference of lee waves over mountain ranges

    Directory of Open Access Journals (Sweden)

    N. I. Makarenko

    2011-01-01

    Full Text Available Internal waves in the atmosphere and ocean are generated frequently from the interaction of mean flow with bottom obstacles such as mountains and submarine ridges. Analysis of these environmental phenomena involves theoretical models of non-homogeneous fluid affected by the gravity. In this paper, a semi-analytical model of stratified flow over the mountain range is considered under the assumption of small amplitude of the topography. Attention is focused on stationary wave patterns forced above the rough terrain. Adapted to account for such terrain, model equations involves exact topographic condition settled on the uneven ground surface. Wave solutions corresponding to sinusoidal topography with a finite number of peaks are calculated and examined.

  4. Atmospheric muons: experimental aspects

    OpenAIRE

    Cecchini, S.; Spurio, M.

    2012-01-01

    We present a review of atmospheric muon flux and energy spectrum measurements over almost six decades of muon momentum. Sea-level and underground/water/ice experiments are considered. Possible sources of systematic errors in the measurements are examinated. The characteristics of underground/water muons (muons in bundle, lateral distribution, energy spectrum) are discussed. The connection between the atmospheric muon and neutrino measurements are also reported.

  5. Atmospheric muons: experimental aspects

    Directory of Open Access Journals (Sweden)

    S. Cecchini

    2012-11-01

    Full Text Available We present a review of atmospheric muon flux and energy spectrum measurements over almost six decades of muon momentum. Sea level and underground/water/ice experiments are considered. Possible sources of systematic errors in the measurements are examined. The characteristics of underground/water muons (muons in bundle, lateral distribution, energy spectrum are discussed. The connection between the atmospheric muon and neutrino measurements are also reported.

  6. Global atmospheric changes.

    OpenAIRE

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the proces...

  7. PROBABILISTIC-STATISTICAL MODELING THE INTERFERENCES FROM ELECTRIC LOCOMOTIVES

    Directory of Open Access Journals (Sweden)

    Orlov A. I.

    2015-02-01

    Full Text Available The movements of electric locomotives create the interferences affecting the wired link. The creation of sufficiently technical effective and at the same time cost-effective means of protection from wireline interferences generated traction networks assumes as a preparatory phase to develop mathematical models of interference caused by electric locomotives. We have developed a probabilistic-statistical model of interferences caused by electric locomotives. The asymptotic distribution of the total interference is the distribution of the length of the two-dimensional random vector whose coordinates - independent normally distributed random variables with mean 0 and variance 1. Limit theorem is proved for the expectation of the total amplitude of the interferences. Monte-Carlo method is used to study the rate of convergence of the expectation of the total amplitude of the interferences to the limiting value. We used an algorithm of mixing developed by MacLaren-Marsaglia (M-algorithm. Five sets of amplitudes are analyzed, selected in accordance with the recommendations of experts in the field of traction AC networks. The most rapid convergence to the limit takes place in the case of equal amplitudes. It was found that the maximum possible average value of the amplitude of the random noise by 7.4% less than the previously used value, which promises a significant economic impact

  8. The effects of menstrual-related pain on attentional interference.

    Science.gov (United States)

    Keogh, Edmund; Cavill, Rebecca; Moore, David J; Eccleston, Christopher

    2014-04-01

    Pain-related attentional interference has been found in both chronic pain and laboratory-inducted pain settings. However, few studies have examined such interference effects during common everyday painful episodes. Menstrual cycle-related pain is a common pain that affects a large number of women on a regular basis. The purpose of the current study was, therefore, to examine the effects of menstrual pain on attentional interference. Fifty-two healthy adult women were tested during 2 different phases of their menstrual cycles: once during a nonpain phase (mid follicular), and once while experiencing menstrual pain (late luteal/early follicular). On each testing session, participants received a battery of 4 attentional interference tasks that included selective attention (flanker task), attention span (n-back task), attentional switching (switching task), and divided attention (dual task). Greater attentional interference effects were found to occur during the menstrual pain phase compared to the nonpain phase. Interestingly, the nature of this effect was a general worsening in performance (e.g., slowing, less accurate), rather than a specific attentional deficit. These results add to a growing literature that generally indicates that attentional interference occurs across a range of different types of pain, including common painful episodes. However, they also highlight that the specific nature of this interference effect may depend on the type pain under consideration. Implications of these findings are also considered.

  9. Adaptive single-antenna transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2011-10-01

    This paper studies the performance of adaptive transmit selection with co-channel interference suppression in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to-interference-plus-noise ratios (SINRs). Two interference cancelation algorithms are considered. The first algorithm assumes that the receiver eliminates the impact of the strongest subset of interferers, whereas the second algorithm suggests random cancelation of interferers to further reduce processing complexity. The impact of outdated ordering of interferers powers on the efficiency of interference cancelation, and the effect of imperfect prediction of transmit channels for desired user adaptation are investigated. Analytical formulations for various performance measures and comparisons between the performance and processing complexity of different adaptation schemes are presented. © 2011 IEEE.

  10. Filter Based Interference Mitigation in Multi Band-OFDM

    Directory of Open Access Journals (Sweden)

    Avila J.

    2014-02-01

    Full Text Available This study aims at to mitigate the interference between the primary user and secondary user in the wireless environment. This becomes necessary task because with the growing demand for bandwidth for wireless connectivity, it has become essential to come up with innovative solutions to tackle the demand. Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM offers a compelling answer for higher bandwidth and data rate requirements. The performance of multi band OFDM has been tarnished by narrow band interference due to the existence of primary users in the UWB spectrum. This occurs due to the leakage of spectral interference power. Despite the fact that Multiband OFDM has the inherent capability to mitigate the interference, independent mitigation techniques become necessary when the interference level is too high. In this study, interference mitigation is carried out by filtering action at the receiver. Results of simulation are compared to analyze the performance of the filters. Further steps have been taken out to enhance the performance of multiband OFDM system which in turn will be helpful in mitigating the interference.

  11. Wide spread spectrum watermarking with side information and interference cancellation

    CERN Document Server

    Guelvouit, Gaëtan Le; 10.1117/12.476839

    2008-01-01

    Nowadays, a popular method used for additive watermarking is wide spread spectrum. It consists in adding a spread signal into the host document. This signal is obtained by the sum of a set of carrier vectors, which are modulated by the bits to be embedded. To extract these embedded bits, weighted correlations between the watermarked document and the carriers are computed. Unfortunately, even without any attack, the obtained set of bits can be corrupted due to the interference with the host signal (host interference) and also due to the interference with the others carriers (inter-symbols interference (ISI) due to the non-orthogonality of the carriers). Some recent watermarking algorithms deal with host interference using side informed methods, but inter-symbols interference problem is still open. In this paper, we deal with interference cancellation methods, and we propose to consider ISI as side information and to integrate it into the host signal. This leads to a great improvement of extraction performance ...

  12. New Parallel Interference Cancellation Scheme for DS/CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    Xu Guo-xiong; Gan Liang-cai; Huang Tian-xi

    2004-01-01

    This paper proposes a new multi-stage parallel interference cancellation scheme by modifying the conventional multi-stage parallel interference canceller (PIC). At each stage, it first converts the interference-cancelled outputs from previous stage into the a prior information, in terms of which the bit mean values are computed and the multi-access interference (MAI) for each user is evaluated, and then an interference cancellation is performed to obtain further interference suppression. To reduce the implementation complexity, we give an approximation expression for bit mean value. The performance over AWGN channel is analyzed and compared to the conventional PIC. The user number K=7 and spreading factor N=13 are chosen as simulation parameters. The computer simulation results show that the proposed PIC has better performance than the conventional PIC both with 2 interference cancellation (IC) stages, at bit error rate of 10-3, for example, about 3 dB performance gain is obtained by using the proposed PIC. It is also shown that our proposed PIC with 1-stage is superior to the conventional PIC with 2-stage in performance, which is of practical value because PIC with fewer stages can bring about shorter processing delay.

  13. Chip-interleaved optical code division multiple access relying on a photon-counting iterative successive interference canceller for free-space optical channels.

    Science.gov (United States)

    Zhou, Xiaolin; Zheng, Xiaowei; Zhang, Rong; Hanzo, Lajos

    2013-07-01

    In this paper, we design a novel Poisson photon-counting based iterative successive interference cancellation (SIC) scheme for transmission over free-space optical (FSO) channels in the presence of both multiple access interference (MAI) as well as Gamma-Gamma atmospheric turbulence fading, shot-noise and background light. Our simulation results demonstrate that the proposed scheme exhibits a strong MAI suppression capability. Importantly, an order of magnitude of BER improvements may be achieved compared to the conventional chip-level optical code-division multiple-access (OCDMA) photon-counting detector.

  14. Similarity interference in learning and retrieving arithmetic facts.

    Science.gov (United States)

    De Visscher, A; Noël, M-P

    2016-01-01

    Storing the solution of simple calculations in long-term memory is an important learning in primary school that is subsequently essential in adult daily living. While most children succeed in storing arithmetic facts to which they have been trained at school, huge individual differences are reported, particularly in children with developmental dyscalculia, who show a severe and persistent deficit in arithmetic facts learning. This chapter reports important advances in the understanding of the development of an arithmetic facts network and focuses on the detrimental effect of similarity interference. First, at the retrieval stage, connectionist models highlighted that the similarity of the neighbor problems in the arithmetic facts network creates interference. More recently, the similarity interference during the learning stage was pointed out in arithmetic facts learning. The interference parameter, that captures the proactive interference that a problem receives from previously learned problems, was shown as a substantial determinant of the performance across multiplication problems. This proactive interference was found both in children and adults and showed that when a problem is highly similar to previously learned ones, it is more difficult to remember it. Furthermore, the sensitivity to this similarity interference determined individual differences in the learning and retrieving of arithmetic facts, giving new insights for interindividual differences. Regarding the atypical development, hypersensitivity-to-interference in memory was related to arithmetic facts deficit in a single case of developmental dyscalculia and in a group of fourth-grade children with low arithmetic facts knowledge. In sum, the impact of similarity interference is shown in the learning stage of arithmetic facts and concerns the typical and atypical development.

  15. Interference of Spin-2 Self-Dual Modes

    CERN Document Server

    Ilha, A; Ilha, Anderson; Wotzasek, Clovis

    2001-01-01

    We study the effects of interference between the self-dual and anti self-dual massive modes of the linearized Einstein-Chern-Simons topological gravity. The dual models to be used in the interference process are carefully analyzed with special emphasis on their propagating spectrum. We identify the opposite dual aspects, necessary for the application of the interference formalism on this model. The soldered theory so obtained displays explicitly massive modes of the Proca type. It may also be written in a form of Polyakov-Weigman identity to a better appreciation of its physical contents.

  16. Coherent Population Trapping-Ramsey Interference in Cold Atoms

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi; YANG Guo-Qing; WANG Jin; ZHAN Ming-Sheng

    2010-01-01

    @@ We demonstrate an experimental observation of coherent population trapping-Ramsey interference in cold 87Rb atoms by employing the time-domain separated oscillatory fields' method. The interference fringe with line width of 80Hz is obtained. We propose a novel method to measure the cold atom number. The measurement is insensitive to the pump beam intensity, the single photon detuning and even the initial state population. We use this method to normalize the interference signal and to improve the signal-to-noise ratio significantly.

  17. Evidence for gluon interference in hadronic Z decays

    Science.gov (United States)

    Acciarri, M.; Adam, A.; Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.; Alpat, B.; Alcaraz, J.; Allaby, J.; Aloisio, A.; Alverson, G.; Alviggi, M. G.; Ambrosi, G.; An, Q.; Anderhub, H.; Andreev, V. P.; Angelescu, T.; Antreasyan, D.; Arefiev, A.; Azemoon, T.; Aziz, T.; Baba, P. V. K. S.; Bagnaia, P.; Baksay, L.; Ball, R. C.; Banerjee, S.; Banicz, K.; Barillère, R.; Barone, L.; Bartalini, P.; Baschirotto, A.; Basile, M.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bencze, Gy. L.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B. L.; Biasini, M.; Biland, A.; Bilei, G. M.; Bizzarri, R.; Blaising, J. J.; Bobbink, G. J.; Bock, R.; Böhm, A.; Borgia, B.; Boucham, A.; Bourilkov, D.; Bourquin, M.; Boutigny, D.; Bouwens, B.; Brambilla, E.; Branson, J. G.; Brigljevic, V.; Brock, I. C.; Bujak, A.; Burger, J. D.; Burger, W. J.; Burgos, C.; Busenitz, J.; Buytenhuijs, A.; Cai, X. D.; Capell, M.; Cara Romeo, G.; Caria, M.; Carlino, G.; Cartacci, A. M.; Casaus, J.; Castellini, G.; Castello, R.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Cesaroni, F.; Chamizo, M.; Chan, A.; Chang, Y. H.; Chaturvedi, U. K.; Chemarin, M.; Chen, A.; Chen, C.; Chen, G.; Chen, G. M.; Chen, H. F.; Chen, H. S.; Chen, M.; Chiefari, G.; Chien, C. Y.; Choi, M. T.; Cifarelli, L.; Cindolo, F.; Civinini, C.; Clare, I.; Clare, R.; Coan, T. E.; Cohn, H. O.; Coignet, G.; Colino, N.; Commichau, V.; Costantini, S.; Cotorobai, F.; de la Cruz, B.; Cui, X. T.; Cui, X. Y.; Dai, T. S.; D'Alessandro, R.; de Asmundis, R.; De Boeck, H.; Degré, A.; Deiters, K.; Dénes, E.; Denes, P.; DeNotaristefani, F.; DiBitonto, D.; Diemoz, M.; Dionisi, C.; Dittmar, M.; Dominguez, A.; Doria, A.; Dorne, I.; Dova, M. T.; Drago, E.; Duchesneau, D.; Duinker, P.; Duran, I.; Dutta, S.; Easo, S.; Efremenko, Yu.; El Mamouni, H.; Engler, A.; Eppling, F. J.; Erné, F. C.; Ernenwein, J. P.; Extermann, P.; Fabbretti, R.; Fabre, M.; Faccini, R.; Falciano, S.; Favara, A.; Fay, J.; Felcini, M.; Ferguson, T.; Fernandez, D.; Fernandez, G.; Ferroni, F.; Fesefeldt, H.; Fiandrini, E.; Field, J. H.; Filthaut, F.; Fisher, P. H.; Forconi, G.; Fredj, L.; Freudenreich, K.; Gailloud, M.; Galaktionov, Yu.; Ganguli, S. N.; Garcia-Abia, P.; Gau, S. S.; Gentile, S.; Gerald, J.; Gheordanescu, N.; Giagu, S.; Goldfarb, S.; Goldstein, J.; Gong, Z. F.; Gonzalez, E.; Gougas, A.; Goujon, D.; Gratta, G.; Gruenewald, M. W.; Gu, C.; Guanziroli, M.; Gupta, V. K.; Gurtu, A.; Gustafson, H. R.; Gutay, L. J.; Hartmann, B.; Hasan, A.; He, J. T.; Hebbeker, T.; Hervé, A.; Hilgers, K.; van Hoek, W. C.; Hofer, H.; Hoorani, H.; Hou, S. R.; Hu, G.; Ilyas, M. M.; Innocente, V.; Janssen, H.; Jin, B. N.; Jones, L. W.; de Jong, P.; Josa-Mutuberria, I.; Kasser, A.; Khan, R. A.; Kamyshkov, Yu.; Kapinos, P.; Kapustinsky, J. S.; Karyotakis, Y.; Kaur, M.; Khokhar, S.; Kienzle-Focacci, M. N.; Kim, D.; Kim, J. K.; Kim, S. C.; Kim, Y. G.; Kinnison, W. W.; Kirkby, A.; Kirkby, D.; Kirkby, J.; Kirsch, S.; Kittel, W.; Klimentov, A.; König, A. C.; Koffeman, E.; Kornadt, O.; Koutsenko, V.; Koulbardis, A.; Kraemer, R. W.; Kramer, T.; Krenz, W.; Kuijten, H.; Kunin, A.; Ladron de Guevara, P.; Landi, G.; Lapoint, C.; Lassila-Perini, K.; Laurikainen, P.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, J.; Lecoq, P.; Le Coultre, P.; Lee, J. S.; Lee, K. Y.; Leggett, C.; Le Goff, J. M.; Leiste, R.; Lenti, M.; Leonardi, E.; Levtchenko, P.; Li, C.; Lieb, E.; Lin, W. T.; Linde, F. L.; Lindemann, B.; Lista, L.; Liu, Y.; Liu, Z. A.; Lohmann, W.; Longo, E.; Lu, W.; Lu, Y. S.; Lübelsmeyer, K.; Luci, L.; Luckey, D.; Ludovici, L.; Luminari, L.; Lustermann, W.; Ma, W. G.; Macchiolo, A.; Maity, M.; Malgeri, L.; Malik, R.; Malinin, A.; Maña, C.; Mangla, S.; Maolinbay, M.; Marchesini, P.; Marin, A.; Martin, J. P.; Marzano, F.; Massaro, G. G. G.; Mazumdar, K.; McNally, D.; Mele, S.; Merk, M.; Merola, L.; Meschini, M.; Wetzger, W. J.; Mi, Y.; Mihul, A.; van Mil, A. J. W.; Mir, Y.; Mirabelli, G.; Mnich, J.; Möller, M.; Monaco, V.; Monteleoni, B.; Moore, R.; Morand, R.; Morganti, S.; Moulai, N. E.; Mount, R.; Müller, S.; Nagy, E.; Nahn, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niaz, M. A.; Nippe, A.; Nowak, H.; Organtini, G.; Ostonen, R.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Pascale, G.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pei, Y. J.; Pensotti, S.; Perret-Gallix, D.; Pevsner, A.; Piccolo, D.; Pieri, M.; Pinto, J. C.; Piroué, P. A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Produit, N.; Qureshi, K. N.; Raghavan, R.; Rahal-Callot, G.; Rancoita, P. G.; Rattaggi, M.; Raven, G.; Razis, P.; Read, K.; Redaelli, M.; Ren, D.; Ren, Z.; Rescigno, M.; Reucroft, S.; Ricker, A.; Riemann, S.; Riemers, B. C.; Riles, K.; Rind, O.; Rizvi, H. A.; Ro, S.; Robohm, A.; Rodin, J.; Rodriguez, F. J.; Roe, B. P.; Röhner, M.; Röhner, S.; Romero, L.; Rosier-Lees, S.; Rosselet, Ph.; van Rossum, W.; Roth, S.; Rubio, J. A.; Rykaczewski, H.; Salicio, J.; Salicio, J. M.; Sanchez, E.; Santocchia, A.; Sarakinos, M. E.; Sarkar, S.; Sartorelli, G.; Sassowsky, M.; Sauvage, G.; Schäfer, C.; Schegelsky, V.; Schmitz, D.; Schmitz, P.; Schneegans, M.; Schoeneich, B.; Scholz, N.; Schopper, H.; Schotanus, D. J.; Schulte, R.; Schultze, K.; Schwenke, J.; Schwering, G.; Sciacca, C.; Sehgal, R.; Seiler, P. G.; Sens, J. C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shukla, J.; Shumilov, E.; Son, D.; Sopczak, A.; Soulimov, V.; Smith, B.; Spickermann, T.; Spillantini, P.; Steuer, M.; Stickland, D. P.; Sticozzi, F.; Stone, H.; Stoyanov, B.; Strauch, K.; Sudhakar, K.; Sultanov, G.; Sun, L. Z.; Susinno, G. F.; Suter, H.; Swain, J. D.; Syed, A. A.; Tang, X. W.; Taylor, L.; Timellini, R.; Ting, Samuel C. C.; Ting, S. M.; Toker, O.; Tonutti, M.; Tonwar, S. C.; Tóth, J.; Tsaregorodtsev, A.; Tsipolitis, G.; Tully, C.; Tuchscherer, H.; Ulbricht, J.; Urbán, L.; Uwer, U.; Valente, E.; Van de Walle, R. T.; Vetlitsky, I.; Viertel, G.; Vikas, P.; Vikas, U.; Vivargent, M.; Voelkert, R.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A. A.; Vorobyov, An. A.; Vuilleumier, L.; Wadhwa, M.; Wallraff, W.; Wang, J. C.; Wang, X. L.; Wang, Y. F.; Wang, Z. M.; Weber, A.; Weill, R.; Willmott, C.; Wittgenstein, F.; Wu, S. X.; Wynhoff, S.; Xu, J.; Xu, Z. Z.; Yang, B. Z.; Yang, C. G.; Yang, G.; Yao, X. Y.; Ye, C. H.; Ye, J. B.; Ye, Q.; Yeh, S. C.; You, J. M.; Yunus, N.; Yzerman, M.; Zaccardelli, C.; Zalite, An.; Zemp, P.; Zeng, J. Y.; Zeng, M.; Zeng, Y.; Zhang, Z.; Zhang, Z. P.; Zhou, B.; Zhou, G. J.; Zhou, J. F.; Zhou, Y.; Zhu, G. Y.; Zhu, R. Y.; Zichichi, A.; van der Zwaan, B. C. C.; L3 Collaboration

    1995-02-01

    We present evidence for soft gluon interference, as required by QCD. This interference is expected to manifest itself in an angular ordering of the gluons radiated within a jet. Using hadronic decays of the Z boson in the L3 detector at LEP, we compare variables sensitive to such an angular ordering, namely the energy-energy correlation asymmetry and the newly introduced particle-particle correlation asymmetry, with the predictions of various parton shower models. Only those models which incorporate the expected interference agree with the data.

  18. Mutual Interference Models for CDMA Mobile Communication Networks

    Directory of Open Access Journals (Sweden)

    K. Hrudkay

    2002-12-01

    Full Text Available Nowadays we are witnesses of a huge development one of the mostprogressive communication technology - mobile networks. The mainproblem in these networks is an elimination of the mutual interference,which, mainly in non-orthogonal CDMA networks, is the principalobstacle for reaching high transmission rates The aim of thiscontribution is to give simplified view to mutual interference modelsfor orthogonal and non-orthogonal CDMA networks. The contribution isintended mainly for PhD. students to help them to obtain an orientationin such a complicated areas, as the interference models for CDMAnetworks are.

  19. Enhanced Kerr nonlinearity via quantum interference from spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Asadpour, S.H., E-mail: S.Hosein.Asadpour@gmail.com [Young Researchers Club, Bandar Anzali Branch, Islamic Azad University, Bandar Anzali (Iran, Islamic Republic of); Sahrai, M. [Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of); Soltani, A. [School of Engineering and Emerging Technologies, University of Tabriz, Tabriz (Iran, Islamic Republic of); Hamedi, H.R. [Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2012-01-02

    A novel atom configuration is proposed for a giant Kerr nonlinearity in zero linear and nonlinear probe absorption. It is shown that without coherent control field and just by quantum interference of spontaneous emission, a giant Kerr nonlinearity can be obtained. -- Highlights: ► The quantum interference from spontaneous emission is considered in a four-level medium. ► The giant Kerr nonlinearity in the zero linear and nonlinear absorption is obtained. ► The quantum interference effect on group velocity is then investigated.

  20. Interference Imaging of Refractive Index Distribution in Thin Samples

    Directory of Open Access Journals (Sweden)

    Norbert Tarjanyi

    2004-01-01

    Full Text Available There are three versions of interference imaging of refractive index distribution in thin samples suggested in this contribution. These are based on imaging of interference field created by waves reflected from the front and the back sample surface or imaging of interference field of Michelson or Mach-Zehnder interferometer with the sample put in one of the interferometers arm. The work discusses the advantages and disadvantages of these techniques and presents the results of imaging of refrective index distribution in photorefractive record of a quasi-harmonic optical field in thin LiNbO3 crystal sample.

  1. Secondary Electron Interference from Trigonal Warping in Clean Carbon Nanotubes

    Science.gov (United States)

    Dirnaichner, A.; del Valle, M.; Götz, K. J. G.; Schupp, F. J.; Paradiso, N.; Grifoni, M.; Strunk, Ch.; Hüttel, A. K.

    2016-10-01

    We investigate Fabry-Perot interference in an ultraclean carbon nanotube resonator. The conductance shows a clear superstructure superimposed onto conventional Fabry-Perot oscillations. A sliding average over the fast oscillations reveals a characteristic slow modulation of the conductance as a function of the gate voltage. We identify the origin of this secondary interference in intervalley and intravalley backscattering processes which involve wave vectors of different magnitude, reflecting the trigonal warping of the Dirac cones. As a consequence, the analysis of the secondary interference pattern allows us to estimate the chiral angle of the carbon nanotube.

  2. A New Approach to Parallel Interference Cancellation for CDMA

    Science.gov (United States)

    Divsalar, Dariush; Simon, Martin

    1996-01-01

    This paper introduces an improved nonlinear parallel interference cancellation scheme that significantly reduces the degrading effect of user interference with implementation complexity linear in the number of users. The scheme operates on the fact that parallel processing simultaneously removes from each user a part of the interference produced by the remaining users accessing the channel the amount being proportional to their reliability. The parallel processing can be done in multiple stages. Simulation results are given for a multitude of different situations, in particular those cases for which the analysis is too complex.

  3. Interference Effects in Strong-Field Dissociative Ionization

    CERN Document Server

    Yue, Lun

    2015-01-01

    We theoretically study dissociative ionization of H$_2^+$ exposed to strong linearly polarized few-cycle visible, near-infrared and midinfrared laser pulses. We find rich energy-sharing structures in the combined electron and nuclear kinetic energy spectra with features that are a priori at odds with simple energy conservation arguments. We explain the structures as interferences between wave packets released during different optical cycles, and during the same optical cycle, respectively. Both inter- and intracycle interference structures are clearly visible in the joint energy spectra. The shapes of the interference structures depend on the dynamics leading to the double continuum, and carry sub-femtosecond information.

  4. Generation of 1D interference patterns of Bloch surface waves

    Science.gov (United States)

    Kadomina, E. A.; Bezus, E. A.; Doskolovich, L. L.

    2016-09-01

    Interference patterns of Bloch surface waves with a period that is significantly less than the wavelength of incident radiation are formed using dielectric diffraction gratings located on the surface of photonic crystal. The simulation based on electromagnetic diffraction theory is used to demonstrate the possibility of high-quality interference patterns due to resonant enhancement of higher evanescent diffraction orders related to the excitation of the Bloch surface waves. The contrast of the interference patterns is close to unity, and the period is less than the period of the diffraction structure by an order of magnitude.

  5. Non-Interference and Erasure Policies for Java Card Bytecode

    DEFF Research Database (Denmark)

    Hansen, René Rydhof; Probst, Christian W.

    2006-01-01

    Non-interference is the property of a program not to leak any secret information. In this paper we propose a notion of non-interference for an abstract version of the Java Card bytecode language. Furthermore an information-flow analysis for verifying non-interference is developed and proved sound...... that confidential information is unavailable after a certain point---and that this unavailability is enforced by the system. This is a crucial requirement for systems like e-commerce or e-voting....

  6. Unreliability of triglyceride measurement to predict turbidity induced interference.

    Science.gov (United States)

    Twomey, P J; Don-Wauchope, A C; McCullough, D

    2003-11-01

    Lipaemic specimens are a common problem in clinical chemistry. Most laboratories will measure the concentration of triglycerides and then decide whether the analytical result is valid or not. There is a poor association between the concentration of triglycerides and an objective assessment of turbidity for visually turbid specimens. Extrapolation of triglyceride concentrations derived from the use of intravenous emulsions to visually turbid specimens found in clinical practice will overestimate the turbidity induced interference in assays (non-turbid interferences are probably the same). The evaluation of turbidity induced interference needs to be standardised using objective assessments of turbidity.

  7. Power allocation scheme for multicell interference coordination in OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    Zhiwei LI; Chunyan FENG; Tiankui ZHANG; Jieying ZHENG

    2009-01-01

    To coordinate inter-cell interference,a multicell adaptive power allocation scheme is proposed for down-link orthogonal frequency division multiple access (OFDMA) cellular systems.This scheme uses the difference of the signal to interference plus noise ratio (SINR) between the co-subchannels of adjacent cells to balance SINR for coordinating the transmit power in the co-subchannels.The scheme can improve edge user performance,reduce interference between the co-subchannels of adjacent cells and improve radio resource utility.Simulation results show that the scheme can balance system performance and ensure system throughput.

  8. An Interference-Aware Traffic-Priority-Based Link Scheduling Algorithm for Interference Mitigation in Multiple Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Thien T. T. Le

    2016-12-01

    Full Text Available Currently, wireless body area networks (WBANs are effectively used for health monitoring services. However, in cases where WBANs are densely deployed, interference among WBANs can cause serious degradation of network performance and reliability. Inter-WBAN interference can be reduced by scheduling the communication links of interfering WBANs. In this paper, we propose an interference-aware traffic-priority-based link scheduling (ITLS algorithm to overcome inter-WBAN interference in densely deployed WBANs. First, we model a network with multiple WBANs as an interference graph where node-level interference and traffic priority are taken into account. Second, we formulate link scheduling for multiple WBANs as an optimization model where the objective is to maximize the throughput of the entire network while ensuring the traffic priority of sensor nodes. Finally, we propose the ITLS algorithm for multiple WBANs on the basis of the optimization model. High spatial reuse is also achieved in the proposed ITLS algorithm. The proposed ITLS achieves high spatial reuse while considering traffic priority, packet length, and the number of interfered sensor nodes. Our simulation results show that the proposed ITLS significantly increases spatial reuse and network throughput with lower delay by mitigating inter-WBAN interference.

  9. LC-MS/MS bioanalytical method development for AMG 900: resolution of an isobaric interference in rodent in vivo studies.

    Science.gov (United States)

    Be, Xuhai; Moore, Earl S; Zhao, Zhiyang; Wells, Mary C

    2013-02-23

    AMG 900 is an orally available small molecule that is a highly potent and selective pan-aurora kinase inhibitor currently in development for the treatment of advanced human cancers. A co-eluting, isobaric interference was discovered in preliminary LC-MS/MS analyses of rodent in vivo pharmacokinetic samples during preclinical evaluation of AMG 900. The interference was identified as a major circulating N-oxide metabolite which partially converted to an [M+H-O](+) ion under the conditions of atmospheric pressure chemical ionization. A selective liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of AMG 900 and its N-oxide metabolite in plasma was developed and successfully applied for the bioanalysis of discovery stage preclinical rodent pharmacokinetic studies.

  10. The role of quantum interference and partial redistribution in the solar Ba II D2 4554 A line

    CERN Document Server

    Smitha, H N; Stenflo, J O; Sampoorna, M

    2014-01-01

    The Ba II D2 line at 4554 A is a good example, where the F-state interference effects due to the odd isotopes produce polarization profiles, which are very different from those of the even isotopes that do not exhibit F-state interference. It is therefore necessary to account for the contributions from the different isotopes to understand the observed linear polarization profiles of this line. In this paper we present radiative transfer modeling with partial frequency redistribution (PRD), which is shown to be essential to model this line. This is because complete frequency redistribution (CRD) cannot reproduce the observed wing polarization. We present the observed and computed Q/I profiles at different limb distances. The theoretical profiles strongly depend on limb distance (\\mu) and the model atmosphere which fits the limb observations fails at other \\mu\\ positions.

  11. Application of thoron interference as a tool for simultaneous measurement of radon and thoron with a pulse ionisation chamber.

    Science.gov (United States)

    Tripathi, R M; Sumesh, C G; Vinod Kumar, A; Puranik, V D

    2013-07-01

    Pulse ionisation chamber (PIC)-based monitors measuring radioactive gas radon ((222)Rn) without energy discrimination will have interference due to thoron ((220)Rn) present in the atmosphere. A technique has been developed to use this property of interference for simultaneous measurement of radon and thoron gas. These monitors work on the principle of counting of gross alphas emitted from radon and its progeny. A theoretical model has been developed for the variation of thoron sensitivity with respect to the flow rate of gas through the monitor. The thoron sensitivity of the monitor is found to vary with the flow rate of gas through the monitor. Using this sensitivity, the sampling procedure has been developed and verified for simultaneous measurement of radon and thoron. The PIC-measured radon and thoron concentration using this procedure agrees well with those measured by using standard radon and thoron discriminating monitor.

  12. Momentum mapping of continuum electron wave packet interference

    CERN Document Server

    Yang, Weifeng; Lin, Cheng; Xu, Jingwen; Sheng, Zhihao; Song, Xiaohong; Hu, Shilin; Chen, Jing

    2016-01-01

    We analyze the two-dimensional photoelectrons momentum distribution of Ar atom ionized by midinfrared laser pulses and mainly concentrate on the energy range below 2Up. By using a generalized quantum trajectory Monte Carlo (GQTMC) simulation and comparing with the numerical solution of time-dependent Schrodinger equation (TDSE), we show that in the deep tunneling regime, the rescattered electron trajectories plays unimportant role and the interplay between the intracycle and inter-cycle results in a ring-like interference pattern. The ring-like interference pattern will mask the holographic interference structure in the low longitudinal momentum region. When the nonadiabatic tunneling contributes significantly to ionization, i.e., the Keldysh parameter 1, the contribution of the rescattered electron trajectories become large, thus holographic interference pattern can be clearly observed. Our results help paving the way for gaining physical insight into ultrafast electron dynamic process with attosecond tempor...

  13. An exact factorization perspective on quantum interferences in nonadiabatic dynamics

    Science.gov (United States)

    Curchod, Basile F. E.; Agostini, Federica; Gross, E. K. U.

    2016-07-01

    Nonadiabatic quantum interferences emerge whenever nuclear wavefunctions in different electronic states meet and interact in a nonadiabatic region. In this work, we analyze how nonadiabatic quantum interferences translate in the context of the exact factorization of the molecular wavefunction. In particular, we focus our attention on the shape of the time-dependent potential energy surface—the exact surface on which the nuclear dynamics takes place. We use a one-dimensional exactly solvable model to reproduce different conditions for quantum interferences, whose characteristic features already appear in one-dimension. The time-dependent potential energy surface develops complex features when strong interferences are present, in clear contrast to the observed behavior in simple nonadiabatic crossing cases. Nevertheless, independent classical trajectories propagated on the exact time-dependent potential energy surface reasonably conserve a distribution in configuration space that mimics one of the exact nuclear probability densities.

  14. An Exact Factorization Perspective on Quantum Interferences in Nonadiabatic Dynamics

    CERN Document Server

    Curchod, Basile F E; Gross, E K U

    2016-01-01

    Nonadiabatic quantum interferences emerge whenever nuclear wavefunctions in different electronic states meet and interact in a nonadiabatic region. In this work, we analyze how nonadiabatic quantum interferences translate in the context of the exact factorization of the molecular wavefunction. In particular, we focus our attention on the shape of the time-dependent potential energy surface - the exact surface on which the nuclear dynamics takes place - using an exactly-solvable model to reproduce different conditions for quantum interferences. The time-dependent potential energy surface develops complex features when strong interferences are present, in clear contrast to the observed behavior in simple nonadiabatic crossing cases. Nevertheless, independent classical trajectories propagated on the exact time-dependent potential energy surface reasonably conserve a distribution in configuration space that mimics the one of the exact nuclear probability density.

  15. Interference Confocal Microscope Integrated with Spatial Phase Shifter.

    Science.gov (United States)

    Wang, Weibo; Gu, Kang; You, Xiaoyu; Tan, Jiubin; Liu, Jian

    2016-08-24

    We present an interference confocal microscope (ICM) with a new single-body four-step simultaneous phase-shifter device designed to obtain high immunity to vibration. The proposed ICM combines the respective advantages of simultaneous phase shifting interferometry and bipolar differential confocal microscopy to obtain high axis resolution, large dynamic range, and reduce the sensitivity to vibration and reflectance disturbance seamlessly. A compact single body spatial phase shifter is added to capture four phase-shifted interference signals simultaneously without time delay and construct a stable and space-saving simplified interference confocal microscope system. The test result can be obtained by combining the interference phase response and the bipolar property of differential confocal microscopy without phase unwrapping. Experiments prove that the proposed microscope is capable of providing stable measurements with 1 nm of axial depth resolution for either low- or high-numerical aperture objective lenses.

  16. Numerical techniques for high-throughput reflectance interference biosensing

    Science.gov (United States)

    Sevenler, Derin; Ünlü, M. Selim

    2016-06-01

    We have developed a robust and rapid computational method for processing the raw spectral data collected from thin film optical interference biosensors. We have applied this method to Interference Reflectance Imaging Sensor (IRIS) measurements and observed a 10,000 fold improvement in processing time, unlocking a variety of clinical and scientific applications. Interference biosensors have advantages over similar technologies in certain applications, for example highly multiplexed measurements of molecular kinetics. However, processing raw IRIS data into useful measurements has been prohibitively time consuming for high-throughput studies. Here we describe the implementation of a lookup table (LUT) technique that provides accurate results in far less time than naive methods. We also discuss an additional benefit that the LUT method can be used with a wider range of interference layer thickness and experimental configurations that are incompatible with methods that require fitting the spectral response.

  17. On Capacity Regions of Interference Channels with Mismatched Local Views

    CERN Document Server

    Kao, David T -H

    2011-01-01

    We study the capacity regions of two-user interference channels where transmitters base their transmission decisions on local views of the channel state. Under the local view model, each transmitter knows only a subset of the four channel gains, which may be mismatched from the other transmitter. We consider a set of seven local views, and find that for five out of the seven local views, TDMA is sufficient to achieve the capacity region of the deterministic interference channel. Conversely for these five views, no policy can achieve a rate point outside the TDMA region without inducing a corner case of sub-TDMA performance in another channel state. The common trait shared by the two remaining local views - those with the potential to outperform TDMA - is transmitter knowledge of the outgoing interference link, emphasizing its importance in creating opportunities to use more advanced schemes. Our conclusions are extended to bounded gap characterizations of the capacity region for the Gaussian interference chan...

  18. Control of the differential interference contrast in reinjected bimode laser

    CERN Document Server

    Lacot, Eric; Hugon, Olivier; de Chatellus, Hugues Guillet

    2016-01-01

    We have demonstrated, both theoretically and experimentally, that it is possible to control (i.e., to enhance or cancel) the contrast of the interference pattern appearing in the intensity images obtained with a laser optical feedback imaging (LOFI) setup using a bimode laser. The laser is composed of two coupled orthogonally polarized states that interact (i.e., interfere) through the cross saturation laser dynamics. We created the contrast control by choosing the frequency shift (i.e., the beating frequency) between the feedback electric fields and the intracavity electric fields. We have shown that the interference contrast of the output power modulation of the laser total intensity is independent from the frequency shift and is always maximal. On the other hand, the interference contrast of each polarization state is frequency dependent. We obtained the maximal contrast when the frequency shift was equal to one of the resonance frequencies of the bimode dynamics, and was very low (and almost cancels) for ...

  19. Blind Adaptive Successive Interference Cancellation for Multicarrier DS-CDMA

    CERN Document Server

    Shakya, Indu; Stipidis, Elias

    2011-01-01

    A new adaptive receiver design for the Multicarrier (MC) DS-CDMA is proposed employing successive interference cancellation (SIC) architecture. One of the main problems limiting the performance of SIC in MC DS-CDMA is the imperfect estimation of multiple access interference (MAI), and hence, the limited frequency diversity gain achieved in multipath fading channels. In this paper, we design a blind adaptive SIC with new multiple access interference suppression capability implemented within despreading process to improve both detection and cancellation processes. Furthermore, dynamic scaling factors derived from the despreader weights are used for interference cancellation process. This method applied on each subcarrier is followed by maximum ratio or equal gain combining to fully exploit the frequency diversity inherent in the multicarrier CDMA systems. It is shown that this way of MAI estimation on individual subcarrier provides significantly improved performance for a MC DS-CDMA system compared to that with...

  20. Quantum interference of molecules -- probing the wave nature of matter

    CERN Document Server

    Venugopalan, Anu

    2012-01-01

    The double slit interference experiment has been famously described by Richard Feynman as containing the "only mystery of quantum mechanics". The history of quantum mechanics is intimately linked with the discovery of the dual nature of matter and radiation. While the double slit experiment for light is easily undertsood in terms of its wave nature, the very same experiment for particles like the electron is somewhat more difficult to comprehend. By the 1920s it was firmly established that electrons have a wave nature. However, for a very long time, most discussions pertaining to interference experiments for particles were merely gedanken experiments. It took almost six decades after the establishment of its wave nature to carry out a 'double slit interference' experiment for electrons. This set the stage for interference experiments with larger particles. In the last decade there has been spectacular progress in matter-wave interefernce experiments. Today, molecules with over a hundred atoms can be made to i...

  1. Linear Transceiver Design for Interference Alignment: Complexity and Computation

    CERN Document Server

    Razaviyayn, Meisam; Luo, Zhi-Quan

    2010-01-01

    Consider a MIMO interference channel whereby each transmitter and receiver are equipped with multiple antennas. The basic problem is to design optimal linear transceivers (or beamformers) that can maximize system throughput. The recent work [1] suggests that optimal beamformers should maximize the total degrees of freedom and achieve interference alignment in high SNR. In this paper we first consider the interference alignment problem in spatial domain and prove that the problem of maximizing the total degrees of freedom for a given MIMO interference channel is NP-hard. Furthermore, we show that even checking the achievability of a given tuple of degrees of freedom for all receivers is NP-hard when each receiver is equipped with at least three antennas. Interestingly, the same problem becomes polynomial time solvable when each transmit/receive node is equipped with no more than two antennas. Finally, we propose a distributed algorithm for transmit covariance matrix design, while assuming each receiver uses a ...

  2. The Michelson interferometer-how to detect invisible interference patterns

    Energy Technology Data Exchange (ETDEWEB)

    Verovnik, Ivo [National Education Institute of Slovenia, Ljubljana, Slovenia (Slovenia); Likar, Andrej [Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana (Slovenia)

    2004-11-12

    In a Michelson interferometer, the contrast of the interference pattern fades away due to incoherence of light when the mirrors are not in equidistant positions. We propose an experiment where the distance between the interference fringes can be determined, even when the difference in length of the interferometer arms is far beyond the coherence length of the light, i.e. when the interference pattern disappears completely for the naked eye. We used a semiconductor laser with two photodiodes as sensors, which enabled us to follow the fluctuations of the light intensity on the screen. The distance between invisible interference fringes was determined from periodic changes of the summed fluctuating signal, obtained by changing the distance between the two sensors.

  3. Electron Interference in Molecular Circular Polarization Attosecond XUV Photoionization

    Directory of Open Access Journals (Sweden)

    Kai-Jun Yuan

    2015-01-01

    Full Text Available Two-center electron interference in molecular attosecond photoionization processes is investigated from numerical solutions of time-dependent Schrödinger equations. Both symmetric H\\(_2^+\\ and nonsymmetric HHe\\(^{2+}\\ one electron diatomic systems are ionized by intense attosecond circularly polarized XUV laser pulses. Photoionization of these molecular ions shows signature of interference with double peaks (minima in molecular attosecond photoelectron energy spectra (MAPES at critical angles \\(\\vartheta_c\\ between the molecular \\(\\textbf{R}\\ axis and the photoelectron momentum \\(\\textbf{p}\\. The interferences are shown to be a function of the symmetry of electronic states and the interference patterns are sensitive to the molecular orientation and pulse polarization. Such sensitivity offers possibility for imaging of molecular structure and orbitals.

  4. Advances in the analysis of pressure interference tests

    Energy Technology Data Exchange (ETDEWEB)

    Martinez R, N. [Petroleos Mexicanos, PEMEX, Mexico City (Mexico); Samaniego V, F. [Univ. Nacional Autonoma de Mexico (Mexico)

    2010-12-15

    This paper presented an extension for radial, linear, and spherical flow conditions of the El-Khatib method for analyzing pressure interference tests through utilization of the pressure derivative. Conventional analysis of interference tests considers only radial flow, but some reservoirs have physical field conditions in which linear or spherical flow conditions prevail. The INTERFERAN system, a friendly computer code for the automatic analysis of pressure interference tests, was also discussed and demonstrated by way of 2 field cases. INTERFERAN relies on the principle of superposition in time and space to interpret a test of several wells with variable histories of production or injection or both. The first field case addressed interference tests conducted in the naturally fractured geothermal field of Klamath Falls, and the second field case was conducted in a river-formed bed in which linear flow conditions are dominant. The analysis was deemed to be reliable. 13 refs., 1 tab., 7 figs.

  5. Interference Cancelation Schemes for Uplink Transmission in Femtocells

    DEFF Research Database (Denmark)

    Thai, Chan; Popovski, Petar

    2010-01-01

    We present techniques that solve the near-far problems in femtocell networks. When a co-channel configuration is used, a transmission in the macrocell may cause interference to a femtocell. We introduce methods to cancel the interference caused by the macrocell to a femtocell by using the high-rate...... link between the macrocell base station (BS) and the femtocell BS. In such a way, the interference from macrocell transmitters is completely cancelled when uplink transmission is used in the femtocell. Therefore, the allocation of time slots for uplink/downlink in a femtocell can be done by trying only...... to minimize the interference that a femtocell terminal experiences during a downlink transmission....

  6. Interference with electrons: from thought to real experiments

    Science.gov (United States)

    Matteucci, Giorgio

    2013-11-01

    The two-slit interference experiment is usually adopted to discuss the superposition principle applied to radiation and to show the peculiar wave behaviour of material particles. Diffraction and interference of electrons have been demonstrated using, as interferometry devices, a hole, a slit, double hole, two-slits, an electrostatic biprism etc. A number of books, short movies and lectures on the web try to popularize the mysterious behaviour of electrons on the basis of Feynman thought experiment which consists of a Young two-hole interferometer equipped with a detector to reveal single electrons. A short review is reported regarding, i) the pioneering attempts carried out to demonstrate that interference patterns could be obtained with single electrons through an interferometer and, ii) recent experiments, which can be considered as the realization of the thought electron interference experiments adopted by Einstein-Bohr and subsequently by Feynman to discuss key features of quantum physics.

  7. Occurrence and characteristics of mutual interference between LIDAR scanners

    Science.gov (United States)

    Kim, Gunzung; Eom, Jeongsook; Park, Seonghyeon; Park, Yongwan

    2015-05-01

    The LIDAR scanner is at the heart of object detection of the self-driving car. Mutual interference between LIDAR scanners has not been regarded as a problem because the percentage of vehicles equipped with LIDAR scanners was very rare. With the growing number of autonomous vehicle equipped with LIDAR scanner operated close to each other at the same time, the LIDAR scanner may receive laser pulses from other LIDAR scanners. In this paper, three types of experiments and their results are shown, according to the arrangement of two LIDAR scanners. We will show the probability that any LIDAR scanner will interfere mutually by considering spatial and temporal overlaps. It will present some typical mutual interference scenario and report an analysis of the interference mechanism.

  8. Interference Alignment as a Rank Constrained Rank Minimization

    CERN Document Server

    Papailiopoulos, Dimitris S

    2010-01-01

    We show that the maximization of the sum degrees-of-freedom for the static flat-fading multiple-input multiple-output (MIMO) interference channel is equivalent to a rank constrained rank minimization problem, when the signal spaces span all available dimensions. The rank minimization corresponds to maximizing interference alignment (IA) such that interference spans the lowest dimensional subspace possible. The rank constraints account for the useful signal spaces spanning all available spatial dimensions. That way, we reformulate all IA requirements to requirements involving ranks. Then, we present a convex relaxation of the RCRM problem inspired by recent results in compressed sensing and low-rank matrix completion theory that rely on approximating rank with the nuclear norm. We show that the convex envelope of the sum of ranks of the interference matrices is the sum of their corresponding nuclear norms and introduce tractable constraints that are asymptotically equivalent to the rank constraints for the ini...

  9. 47 CFR 15.712 - Interference protection requirements.

    Science.gov (United States)

    2010-10-01

    ... Television Band Devices § 15.712 Interference protection requirements. (a) Digital television stations, and... Mexico. (1) Fixed and personal/portable TVBDs shall not operate within 32 kilometers of the...

  10. Interference Networks with Point-to-Point Codes

    CERN Document Server

    Baccelli, Francois; Tse, David

    2011-01-01

    The paper establishes the capacity region of the Gaussian interference channel with many transmitter-receiver pairs constrained to use point-to-point codes. The capacity region is shown to be strictly larger in general than the achievable rate regions when treating interference as noise, using successive interference cancellation decoding, and using joint decoding. The gains in coverage and achievable rate using the optimal decoder are analyzed in terms of ensemble averages using stochastic geometry. In a spatial network where the nodes are distributed according to a Poisson point process and the channel path loss exponent is $\\beta > 2$, it is shown that the density of users that can be supported by treating interference as noise can scale no faster than $B^{2/\\beta}$ as the bandwidth $B$ grows, while the density of users can scale linearly with $B$ under optimal decoding.

  11. Assay of methylglyoxal and glyoxal and control of peroxidase interference.

    Science.gov (United States)

    Thornalley, Paul J; Rabbani, Naila

    2014-04-01

    Methylglyoxal and glyoxal are endogenous α-oxoaldehyde metabolites and substrates of the glyoxalase system. These and related α-oxoaldehydes are often determined in cell, tissue and body fluid samples by derivatization with 1,2-diaminobenzene and similar compounds. Peroxidase activity in physiological tissues is a potential interference in estimation of methylglyoxal and glyoxal as it catalyses the conversion of 1,2-diaminobenzene into trace amounts of these dicarbonyl metabolites. Residual peroxidase activity in deproteinized extracts is found to cause significant interference in methylglyoxal and glyoxal estimations. This interference is blocked by the addition of sodium azide in the derivatizing buffer. Estimates of methylglyoxal concentration thereby obtained are in keeping with those predicted by systems modelling of methylglyoxal glycation kinetics in situ. Blocking sample peroxidase activity is important to avoid overestimation in the measurement of glyoxal and methylglyoxal. A dicarbonyl assay protocol resistant to interferences is described in the present article.

  12. Pattern-integrated interference lithography: prospects for nano- and microelectronics.

    Science.gov (United States)

    Leibovici, Matthieu C R; Burrow, Guy M; Gaylord, Thomas K

    2012-10-08

    In recent years, limitations in optical lithography have challenged the cost-effective manufacture of nano- and microelectronic chips. Spatially regular designs have been introduced to improve manufacturability. However, regular designed layouts typically require an interference step followed by a trim step. These multiple steps increase cost and reduce yield. In the present work, Pattern-Integrated Interference Lithography (PIIL) is introduced to address this problem. PIIL is the integration of interference lithography and superposed pattern mask imaging, combining the interference and the trim into a single-exposure step. Example PIIL implementations and experimental demonstrations are presented. The degrees of freedom associated with the source, pattern mask, and Fourier filter designs are described.

  13. Tracking Launch Vehicles in Interference and Jamming Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MARK Resources proposes to develop a method for combining a set of distributed FRPAs into a network that provides high GPS anti-jam/interference capability. Like a...

  14. Constructive interference via collision-aided radiative excitation

    Institute of Scientific and Technical Information of China (English)

    杨希华; 孙真荣; 丁良恩; 王祖赓

    2002-01-01

    We have studied theoretically constructive interference via collision-aided radiative excitation in an open fourlevel system using a density matrix approach. The four-level system consists of a A-type three-level quantum-beat configuration driven by one laser field and a fourth level coupled by a vacuum mode. It is shown that through the incoherent process (collision), coherence between widely-separated doublets and subsequent constructive interference can be realized. We analyse the effects of the collisio-induced coherent and incoherent decay rates, laser intensity, and energy separation of the doublets on the interference.Meanwhile, the constructive interference between the two transition pathways 3P1/2-4D and 3P3/2-4D via equal-frequency hybrid excitation and collision-aided radiative excitation in an Na2-Na system is experimentally observed. A good agreement between the theoretical and experimental results is obtained.

  15. An update on mobile phones interference with medical devices.

    Science.gov (United States)

    Mahmoud Pashazadeh, Ali; Aghajani, Mahdi; Nabipour, Iraj; Assadi, Majid

    2013-10-01

    Mobile phones' electromagnetic interference with medical devices is an important issue for the medical safety of patients who are using life-supporting medical devices. This review mainly focuses on mobile phones' interference with implanted medical devices and with medical equipment located in critical areas of hospitals. A close look at the findings reveals that mobile phones may adversely affect the functioning of medical devices, and the specific effect and the degree of interference depend on the applied technology and the separation distance. According to the studies' findings and the authors' recommendations, besides mitigating interference, using mobile phones at a reasonable distance from medical devices and developing technology standards can lead to their effective use in hospital communication systems.

  16. Improving Dense Network Performance through Centralized Scheduling and Interference Coordination

    DEFF Research Database (Denmark)

    Lopez, Victor Fernandez; Pedersen, Klaus I.; Alvarez, Beatriz Soret

    2017-01-01

    . Interference management at the receiver is achieved through the use of a Network-Assisted Interference Cancellation and Suppression (NAICS) receiver. In order to further boost the 5th percentile user data rates, the transmission rank at the interferers is selectively reduced by a centralized rank coordination......Dense network deployments comprising small cells pose a series of important challenges when it comes to achieving an efficient resource use and curbing inter-cell interference in the downlink. This article examines different techniques to treat these problems in a dynamic way, from the network...... and the receiver sides. As a network coordination scheme, we apply a centralized joint cell association and scheduling mechanism based on dynamic cell switching, by which users are not always served by the strongest perceived cell. The method simultaneously resultsin more balanced loads and increased performance...

  17. Mode interference patterns in retinal receptor outer segments

    NARCIS (Netherlands)

    Wijngaard, W.

    1974-01-01

    Some calculated interference patterns of electromagnetic modes are given for a dielectric waveguide representative for the receptor outer segment. The results are qualitatively in accordance with observations of Enoch.

  18. Maximum MIMO System Mutual Information with Antenna Selection and Interference

    Directory of Open Access Journals (Sweden)

    Rick S. Blum

    2004-05-01

    Full Text Available Maximum system mutual information is considered for a group of interfering users employing single user detection and antenna selection of multiple transmit and receive antennas for flat Rayleigh fading channels with independent fading coefficients for each path. In the case considered, the only feedback of channel state information to the transmitter is that required for antenna selection, but channel state information is assumed at the receiver. The focus is on extreme cases with very weak interference or very strong interference. It is shown that the optimum signaling covariance matrix is sometimes different from the standard scaled identity matrix. In fact, this is true even for cases without interference if SNR is sufficiently weak. Further, the scaled identity matrix is actually that covariance matrix that yields worst performance if the interference is sufficiently strong.

  19. Estimation with a helper who knows the interference

    CERN Document Server

    Chia, Yeow-Khiang; Weissman, Tsachy

    2012-01-01

    We consider the problem of estimating a signal corrupted by independent interference with the assistance of a cost-constrained helper who knows the interference causally or noncausally. When the interference is known causally, we characterize the minimum distortion incurred in estimating the desired signal. In the noncausal case, we present a general achievable scheme for discrete memoryless systems and novel lower bounds on the distortion for the binary and Gaussian settings. Our Gaussian setting coincides with that of assisted interference suppression introduced by Grover and Sahai. Our lower bound for this setting is based on the relation recently established by Verd\\'u between divergence and minimum mean squared error. We illustrate with a few examples that this lower bound can improve on those previously developed. Our bounds also allow us to characterize the optimal distortion in several interesting regimes. Moreover, we show that causal and noncausal estimation are not equivalent for this problem. Fina...

  20. Atmospheric Laser Communication.

    Science.gov (United States)

    Fischer(, Kenneth W.; Witiw, Michael R.; Baars+, Jeffrey A.; Oke, T. R.

    2004-05-01

    Atmospheric laser communication, often referred to as free-space optics (FSO) or free-space laser (FSL) communication, is similar to fiber optic cable in terms of carrier wavelength and bandwidth capability, but data are transmitted directly through the atmosphere via laser beams over paths from a few meters to 4 km or longer. FSL uses lasers in the near-infrared spectrum, typically at wavelengths of 850 or 1550 nm. Given these wavelengths, atmospheric attenuation must be considered, and an adequate margin of optical power (dB) must exist to support high system availability (the percentage of time that an FSL link is in operation, typically 99.9%). A visual range of 100 m can attenuate a laser beam at a rate of nearly 130 dB km-1. For short links (rain, and snow frequently become issues. To address these issues, long-term climate data are analyzed to determine the frequency of occurrence of low visibilities and low-cloud ceilings. To estimate availability at a site of interest, adjustments to airport climate data are made to accommodate differences in altitude, geography, and the effects of the urban heat island. In sum, communication via FSL is a feasible alternative to fiber optic cable when atmospheric conditions are considered and properly analyzed.(Current affiliation: The Boeing Company, Seattle, Washington+Current affiliation: Department of Atmospheric Sciences, University of Washington, Seattle, Washington

  1. Scattering Induced Quantum Interference of Multiple Quantum Optical States

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Wubs, Martijn; Mortensen, N. Asger;

    2011-01-01

    Using a discrete mode theory for propagation of quantum optical states, we investigate the consequences of multiple scattering on the degree of quadrature entanglement and quantum interference. We report that entangled states can be created by multiple-scattering. We furthermore show that quantum...... interference induced by the transmission of quantized light through a multiple-scattering medium will persist even after averaging over an ensemble of scattering samples....

  2. Mutual Interference Models for CDMA Mobile Communication Networks

    OpenAIRE

    Hrudkay, K.; Wieser, V.

    2002-01-01

    Nowadays we are witnesses of a huge development one of the most progressive communication technology - mobile networks. The main problem in these networks is an elimination of the mutual interference, which, mainly in non-orthogonal CDMA networks, is the principal obstacle for reaching high transmission rates The aim of this contribution is to give simplified view to mutual interference models for orthogonal and non-orthogonal CDMA networks. The contribution is intended mainly for PhD. studen...

  3. Superluminal light propagation via quantum interference in decay channels

    OpenAIRE

    Arun, R.

    2016-01-01

    We examine the propagation of a weak probe light through a coherently driven $Y$-type system. Under the condition that the excited atomic levels decay via same vacuum modes, the effects of quantum interference in decay channels are considered. It is found that the interference in decay channels results in a lossless anomalous dispersion between two gain peaks. We demonstrate that the probe pulse propagation can in principle be switched from subluminal to superluminal due to the decay-induced ...

  4. Susceptibility of sensor networks to intentional electromagnetic interference

    OpenAIRE

    Delsing, Jerker; Ekman, Jonas; Johansson, Jonny; Sundberg, Sofia; Bäckström, Mats; Nilsson, T.

    2006-01-01

    It is reasonable to think that sensor networks might be part of society critical systems in the future. Therefor this paper discusses and shows the vulnerabilities of sensor networks to intentional electromagnetic interference (IEMI). Principle ways of sensor network IEMI is addressed and followed by a discussion on schemes for protection. Experimental results for both in-band and exband interference from low- and high- level sources is reported. It is obvious that more emphasis has to be put...

  5. SOME BLIND FRESH EQUALIZATION ALGORITHMS WITH ANTI-INTERFERENCE CAPABILITIES

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Some novel blind FREquency.Shift (FRESH) equalizer algorithms axe proposed for the equalization of Finite Impulse Response(FIR)single channel with anti-interference capabilities.These algorithms based on FRESH filter can work well without any training sequence.Simulation results show that the equalizer algorithms can effectively reject many types of interferences and the performances of these new equalizer algorithms are superior to the conventional equalizer algorithms.

  6. Inference for deformation and interference in 3D printing

    OpenAIRE

    Sabbaghi, Arman; Dasgupta, Tirthankar; Huang, Qiang; Zhang, Jizhe

    2014-01-01

    Additive manufacturing, or 3D printing, is a promising manufacturing technique marred by product deformation due to material solidification in the printing process. Control of printed product deformation can be achieved by a compensation plan. However, little attention has been paid to interference in compensation, which is thought to result from the inevitable discretization of a compensation plan. We investigate interference with an experiment involving the application of discretized compen...

  7. Italian, French, Polish: in the Bermuda Triangle of linguistic interference

    OpenAIRE

    Małgorzata Balicka

    2009-01-01

    Increasing contacts between nations make people learn foreign languages. Unfortunately, the use of more than one language system may cause errors due to linguistic interference. In the present paper we consider different definitions of this phenomenon and describe the conditions reąuired for its presence, along with proposals on how to eliminate interference mistakes. A specific case is false friends, words similar in form but different in meaning, which can lead to misunderstandings or even ...

  8. General relativistic effects in quantum interference of "clocks"

    CERN Document Server

    Zych, Magdalena; Costa, Fabio; Brukner, Časlav

    2016-01-01

    Quantum mechanics and general relativity have been each successfully tested in numerous experiments. However, the regime where both theories are jointly required to explain physical phenomena remains untested by laboratory experiments, and is also not fully understood by theory. This contribution reviews recent ideas for a new type of experiments: quantum interference of "clocks", which aim to test novel quantum effects that arise from time dilation. "Clock" interference experiments could be realised with atoms or photons in near future laboratory experiments.

  9. Influence of Occlusal Interference on the Prevalence of Temporomandibular Disorders

    OpenAIRE

    Ćelić, R.; Pandurić, J.; Badel, T.; Kraljević, S.; Dulčić, N.

    2002-01-01

    The significance of occlusal interference in the etiology of temporomandibular disorders has been questioned in numerous recent articles. The aim of this study was to determine the prevalence of the clinical signs and symptoms of temporomandibular disorders in a young male nonpatient population and to investigate a possible association between the signs and symptoms of temporomandibular disorders and occlusal interference. A questionnaire including data from history and clinical functional ...

  10. An Automatic Interference Recognition Method in Spread Spectrum Communication System

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-ming; TAO Ran

    2007-01-01

    An algorithm to detect and recognize interferences embedded in a direct sequence spread spectrum (DSSS) communication system is proposed. Based on Welch's averaging modified periodogram method and fractional Fourier transformation (FRFT), the paper proposes a decision tree-based algorithm in which a set of decision criteria for identifying different types of interferences is developed. Simulation results demonstrate that the proposed algorithm provides a high recognition rate and is robust for various ISR and SNR.

  11. Co-Channel Interference Mitigation Using Satellite Based Receivers

    Science.gov (United States)

    2014-12-01

    While there is some phase noise present in the continuous time-shifted signal, it is important to recognize that this signal is plotted over the [−π...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RECEIVERS by John E. Patterson...07-02-2012 to 12-19-2014 4. TITLE AND SUBTITLE CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RE- CEIVERS 5. FUNDING NUMBERS 6. AUTHOR(S

  12. Automotive radar – investigation of mutual interference mechanisms

    OpenAIRE

    2010-01-01

    In the past mutual interference between automotive radar sensors has not been regarded as a major problem. With an increasing number of such systems, however, this topic is receiving more and more attention. The investigation of mutual interference and countermeasures is therefore one topic of the joint project "Radar on Chip for Cars" (RoCC) funded by the German Federal Ministry of Education and Research (BMBF). RoCC's goal is to pave the way for the development of high-per...

  13. Research on the method of precise alignment technology of atmospheric laser communication

    Science.gov (United States)

    Chen, Wen-jian; Gao, Wei; Duan, Yuan-yuan; Ma, Shi-wei; Chen, Jian

    2016-10-01

    Atmosphere laser communication takes advantage of laser as the carrier transmitting the voice, data, and image information in the atmosphere. Because of its high reliability, strong anti-interference ability, the advantages of easy installation, it has great potential and development space in the communications field. In the process of establish communication, the capture, targeting and tracking of the communication signal is the key technology. This paper introduce a method of targeting the signal spot in the process of atmosphere laser communication, which through the way of making analog signal addition and subtraction directly and normalized to obtain the target azimuth information to drive the servo system to achieve precise alignment of tracking.

  14. Cyclostationary Model Based Multiple-Tone Interference Rejection in DSSS Communication Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Multiple-tone interference is a kind of narrow band interference appears in Direct Sequence (DS) Spread Spectrum (SS) communication system frequently that degrades the system performance. Most open literature studies on narrowband interference rejection assumed stationary SS signal and interference. SS signal and interference are modeled as cyclostationary and based on cyclostationary model, an interference rejection algorithm is proposed. Through computer simulation, it is shown that the performance of the SS system can be improved considerably after adopting this algorithm.

  15. Atmosphere and Ambient Space

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Atmosphere and Ambient Space This paper explores the relation between atmosphere and ambient space. Atmosphere and ambient space share many salient properties. They are both ontologically indeterminate, constantly varying and formally diffuse and they are both experienced as a subtle, non......-signifying property of a given space. But from a certain point of view, the two concepts also designate quite dissimilar experiences of space. To be ’ambient’ means to surround. Accordingly, ambient space is that space, which surrounds something or somebody. (Gibson 1987: 65) Since space is essentially...... of a surrounding character, all space can thus be described as having a fundamentally ambient character. So what precisely is an ambient space, then? As I will argue in my presentation, ambient space is a sensory effect of spatiality when a space is experienced as being particularly surrounding: a ‘space effect...

  16. Phenomenology of atmospheric neutrinos

    Directory of Open Access Journals (Sweden)

    Fedynitch Anatoli

    2016-01-01

    Full Text Available The detection of astrophysical neutrinos, certainly a break-through result, introduced new experimental challenges and fundamental questions about acceleration mechanisms of cosmic rays. On one hand IceCube succeeded in finding an unambiguous proof for the existence of a diffuse astrophysical neutrino flux, on the other hand the precise determination of its spectral index and normalization requires a better knowledge about the atmospheric background at hundreds of TeV and PeV energies. Atmospheric neutrinos in this energy range originate mostly from decays of heavy-flavor mesons, which production in the phase space relevant for prompt leptons is uncertain. Current accelerator-based experiments are limited by detector acceptance and not so much by the collision energy. This paper recaps phenomenological aspects of atmospheric leptons and calculation methods, linking recent progress in flux predictions with particle physics at colliders, in particular the Large Hadron Collider.

  17. Observations of Exoplanet Atmospheres

    CERN Document Server

    Crossfield, Ian J M

    2015-01-01

    Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics & circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly-imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.

  18. Atmospheres of Brown Dwarfs

    CERN Document Server

    Helling, Christiane

    2014-01-01

    Brown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of < 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.

  19. CONTEXTUAL INTERFERENCE AND INTROVERSION/EXTRAVERSION IN MOTOR LEARNING.

    Science.gov (United States)

    Meira, Cassio M; Fairbrother, Jeffrey T; Perez, Carlos R

    2015-10-01

    The Introversion/Extraversion dimension may interact with contextual interference, as random and blocked practice schedules imply distinct levels of variation. This study investigated the effect of different practice schedules in the acquisition of a motor skill in extraverts and introverts. Forty male undergraduate students (M = 24.3 yr., SD = 5.6) were classified as extraverts (n = 20) and introverts (n = 20) by the Eysenck Personality Questionnaire and allocated in one of two practice schedules with different levels of contextual interference: blocked (low contextual interference) and random (high contextual interference). Half of each group was assigned to a blocked practice schedule, and the other half was assigned to a random practice schedule. The design had two phases: acquisition and transfer (5 min. and 24 hr.). The participants learned variations of a sequential timing keypressing task. Each variation required the same sequence but different timing; three variations were used in acquisition, and one variation of intermediate length was used in transfer. Results for absolute error and overall timing error (root mean square error) indicated that the contextual interference effect was more pronounced for introverts. In addition, introverts who practiced according to the blocked schedule committed more errors during the 24-hr. transfer, suggesting that introverts did not appear to be challenged by a low contextual interference practice schedule.

  20. Imperfect generalized transmit beamforming with co-channel interference cancelation

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-10-01

    The performance of a generalized single-stream transmit beamforming scheme employing receive co-channel interference -steering algorithms in slowly varying and flat fading channels is analyzed. The impact of imperfect prediction of channel state information (CSI) for the desired user spatially uncorrelated transmit channels is considered. Both dominant interference cancelation and adaptive arbitrary interference cancelation algorithms for closely spaced receive antennas are used. The impact of outdated statistical ordering of the interferers instantaneous powers on the effectiveness of dominant interference cancelation is investigated against the less complex adaptive arbitrary cancelation scheme. For the system models described above, new exact formulas for the statistics of combined signal-to-interference-plus-noise ratio (SINR) are derived, from which results for conventional maximum ratio transmission (MRT) and best transmit channel selection schemes can be deduced as limiting cases. The results presented herein can be used to obtain quantitative measure for various performance metrics, and in addition to investigate the performance-complexity tradeoff for different multiple-antenna system models. © 2010 IEEE.

  1. CRISPR interference and priming varies with individual spacer sequences.

    Science.gov (United States)

    Xue, Chaoyou; Seetharam, Arun S; Musharova, Olga; Severinov, Konstantin; Brouns, Stan J J; Severin, Andrew J; Sashital, Dipali G

    2015-12-15

    CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring 'spacer' sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for destruction through CRISPR interference. Mutations in the protospacer adjacent motif (PAM) and seed regions block interference but promote rapid 'primed' adaptation. Here, we use multiple spacer sequences to reexamine the PAM and seed sequence requirements for interference and priming in the Escherichia coli Type I-E CRISPR-Cas system. Surprisingly, CRISPR interference is far more tolerant of mutations in the seed and the PAM than previously reported, and this mutational tolerance, as well as priming activity, is highly dependent on spacer sequence. We identify a large number of functional PAMs that can promote interference, priming or both activities, depending on the associated spacer sequence. Functional PAMs are preferentially acquired during unprimed 'naïve' adaptation, leading to a rapid priming response following infection. Our results provide numerous insights into the importance of both spacer and target sequences for interference and priming, and reveal that priming is a major pathway for adaptation during initial infection.

  2. Two-photon interference of temporally separated photons

    Science.gov (United States)

    Kim, Heonoh; Lee, Sang Min; Moon, Han Seb

    2016-10-01

    We present experimental demonstrations of two-photon interference involving temporally separated photons within two types of interferometers: a Mach-Zehnder interferometer and a polarization-based Michelson interferometer. The two-photon states are probabilistically prepared in a symmetrically superposed state within the two interferometer arms by introducing a large time delay between two input photons; this state is composed of two temporally separated photons, which are in two different or the same spatial modes. We then observe two-photon interference fringes involving both the Hong-Ou-Mandel interference effect and the interference of path-entangled two-photon states simultaneously in a single interferometric setup. The observed two-photon interference fringes provide simultaneous observation of the interferometric properties of the single-photon and two-photon wavepackets. The observations can also facilitate a more comprehensive understanding of the origins of the interference phenomena arising from spatially bunched/anti-bunched two-photon states comprised of two temporally separated photons within the interferometer arms.

  3. Interference effects between manual and oral motor skills.

    Science.gov (United States)

    Gagné, Marie-Hélène; Cohen, Henri

    2016-03-01

    Consolidation of a motor skill is characterized by spontaneous improvement in performance between practice sessions. These offline gains can be eliminated if another skill is introduced soon afterward-a phenomenon called retroactive interference. Interference effects have been found in studies using two similar tasks involving the same motor effectors in a manual mode. The present study aimed to determine the extent to which differences in motor production mode modulate interference in skill learning. Healthy participants were assigned to one of three conditions and trained on a finger opposition sequence (FOS) learning task. All subjects were tested 24 h later on the original FOS learning task. Control subjects who were not exposed to a secondary learning task exhibited the expected offline gains after 24 h. Subjects who immediately learned a secondary task after the FOS training, either in the same manual mode (French Sign Language) or in an oral mode (CVC syllables), did not show any offline gains. Interestingly, the amount of interference was equivalent in the manual and oral learning conditions. The results reveal that interference effects in motor skill learning can occur when different effectors are involved in the primary and secondary tasks. The sequence processing abilities of the basal ganglia appear to play a major role in these interference effects.

  4. Cognitive Aware Interference Mitigation Scheme for OFDMA Femtocells

    KAUST Repository

    Alqerm, Ismail

    2015-04-09

    Femto-cells deployment in today’s cellular networks came into practice to fulfill the increasing demand for data services. It also extends the coverage in the indoor areas. However, interference to other femto and macro-cells users remains an unresolved challenge. In this paper, we propose an interference mitigation scheme to control the cross-tier interference caused by femto-cells to the macro users and the co-tier interference among femtocells. Cognitive radio spectrum sensing capability is utilized to determine the non-occupied channels or the ones that cause minimal interference to the macro users. An awareness based channel allocation scheme is developed with the assistance of the graph-coloring algorithm to assign channels to the femto-cells base stations with power optimization, minimal interference, maximum throughput, and maximum spectrum efficiency. In addition, the scheme exploits negotiation capability to match traffic load and QoS with the channel, and to maintain efficient utilization of the available channels.

  5. Cross Layer Interference Management in Wireless Biomedical Networks

    Directory of Open Access Journals (Sweden)

    Emmanouil G. Spanakis

    2014-04-01

    Full Text Available Interference, in wireless networks, is a central phenomenon when multiple uncoordinated links share a common communication medium. The study of the interference channel was initiated by Shannon in 1961 and since then this problem has been thoroughly elaborated at the Information theoretic level but its characterization still remains an open issue. When multiple uncoordinated links share a common medium the effect of interference is a crucial limiting factor for network performance. In this work, using cross layer cooperative communication techniques, we study how to compensate interference in the context of wireless biomedical networks, where many links transferring biomedical or other health related data may be formed and suffer from all other interfering transmissions, to allow successful receptions and improve the overall network performance. We define the interference limited communication range to be the critical communication region around a receiver, with a number of surrounding interfering nodes, within which a successful communication link can be formed. Our results indicate that we can achieve more successful transmissions by adapting the transmission rate and power, to the path loss exponent, and the selected mode of the underline communication technique allowing interference mitigation and when possible lower power consumption and increase achievable transmission rates.

  6. Interference-aware random beam selection for spectrum sharing systems

    KAUST Repository

    Abdallah, Mohamed M.

    2012-09-01

    Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing secondary unlicensed networks to share the spectrum with primary licensed networks under acceptable interference levels to the primary users. In this paper, we develop interference-aware random beam selection schemes that provide enhanced throughput for the secondary link under the condition that the interference observed at the primary link is within a predetermined acceptable value. For a secondary transmitter equipped with multiple antennas, our schemes select a random beam, among a set of power- optimized orthogonal random beams, that maximizes the capacity of the secondary link while satisfying the interference constraint at the primary receiver for different levels of feedback information describing the interference level at the primary receiver. For the proposed schemes, we develop a statistical analysis for the signal-to-noise and interference ratio (SINR) statistics as well as the capacity of the secondary link. Finally, we present numerical results that study the effect of system parameters including number of beams and the maximum transmission power on the capacity of the secondary link attained using the proposed schemes. © 2012 IEEE.

  7. Interference Mitigation Techniques for Spectral Capacity Enhancement in GSM Networks

    Directory of Open Access Journals (Sweden)

    Ahmed M. Alaa

    2014-01-01

    Full Text Available Random Frequency Hopping (FH is a key feature of GSM networks that allows for capacity enhancement. The increased co-channel interference experienced in networks with tight frequency reuse schemes can be mitigated by adopting frequency hopping. Frequency hopping diversifies the interference signals over sparse transmitted bursts. This effect is called Interference Diversity. Interference Diversity allows the Forward Error Correcting codes (FEC to easily correct the corrupted bits. Thus, frequency hopping allows the network operator to use a tighter frequency reuse scheme without exhibiting higher levels of co-channel interference. Discontinuous Transmission (DTX is another interference mitigation method that utilizes the user’s silence frames to reduce the transmitted power, while Power Control (PC links the transmitted handset power with its relative distance from the Base Station (BTS. In this work, we study the impact of random FH, DTX and PC on the Spectral Capacity of GSM cellular networks by means of combined link level and system level simulation. It is shown that a spectral capacity gain is obtained in a 3/9 reuse scheme that deploys PC, DTX and FH compared to a conventional 4/12 reuse scheme.

  8. Moxidectin interference on motor activity of rats

    Directory of Open Access Journals (Sweden)

    Patrícia de Sá e Benevides Rodrigues-Alves

    2009-08-01

    Full Text Available The present study investigated the effects of t moxidectin (MXD in some parameters of rat motor function and neurochemical. The general activity in the open field and the motor coordination in the wooden beam were employed to evaluate the MXD effects. The results showed that, in the open field, even at high doses (2.0 and 20.0 mg/kg, the MXD did not alter the locomotion and the rearing frequencies. However, MXD was able to impair the motor coordination of the animals at wooden beam. Neurochemical studies of striatal GABA and dopamine neurotransmitters showed a reduced levels of dopamine and its metabolite, homovanillic acid, without interference on striatal GABA levels. Since GABAergic receptor stimulation had an inhibitory effect on dopaminergic striatal system, the decreased motor coordination could be attributed to an action of MXD on dopamine system via GABA activation.A moxidectina (MXD é uma droga antiparasitária amplamente empregada em animais domésticos; seu mecanismo de ação, em mamíferos, envolve o neurotransmissor ácido gama-aminobutírico (GABA. Esse neurotransmissor tem papel importante na função motora. Assim, no presente trabalho estudaram-se os efeitos da MXD em alguns parâmetros comportamentais ligados a função motora de ratos e também em sistemas de neurotransmissão central. A atividade geral no campo aberto e a coordenação motora na trave elevada foram empregadas para avaliar os efeitos de diferentes doses de MXD. Os resultados mostraram que: no campo aberto, mesmo as doses maiores (2.0 e 20.0 mg/kg de MXD não alteraram as freqüências de locomoção e levantar. Por outro lado, a MXD foi capaz de prejudicar a coordenação motora dos animais avaliada na trave elevada. Estudos neuroquímicos dos níveis estriatais de GABA e dopamina mostraram redução dos níveis de dopamina e seu metabólito, ácido homavanílico, sem interferência nos níveis de GABA estriatal. Considerando que a estimulação de

  9. Dreaming of Atmospheres

    Science.gov (United States)

    Waldmann, Ingo

    2016-10-01

    Radiative transfer retrievals have become the standard in modelling of exoplanetary transmission and emission spectra. Analysing currently available observations of exoplanetary atmospheres often invoke large and correlated parameter spaces that can be difficult to map or constrain.To address these issues, we have developed the Tau-REx (tau-retrieval of exoplanets) retrieval and the RobERt spectral recognition algorithms. Tau-REx is a bayesian atmospheric retrieval framework using Nested Sampling and cluster computing to fully map these large correlated parameter spaces. Nonetheless, data volumes can become prohibitively large and we must often select a subset of potential molecular/atomic absorbers in an atmosphere.In the era of open-source, automated and self-sufficient retrieval algorithms, such manual input should be avoided. User dependent input could, in worst case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is build to address these issues. RobERt is a deep belief neural (DBN) networks trained to accurately recognise molecular signatures for a wide range of planets, atmospheric thermal profiles and compositions. Using these deep neural networks, we work towards retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from current and past data and make sensible qualitative preselections of atmospheric opacities to be used for the quantitative stage of the retrieval process.In this talk I will discuss how neural networks and Bayesian Nested Sampling can be used to solve highly degenerate spectral retrieval problems and what 'dreaming' neural networks can tell us about atmospheric characteristics.

  10. Target-in-the-loop remote sensing of laser beam and atmospheric turbulence characteristics.

    Science.gov (United States)

    Vorontsov, Mikhail A; Lachinova, Svetlana L; Majumdar, Arun K

    2016-07-01

    A new target-in-the-loop (TIL) atmospheric sensing concept for in situ remote measurements of major laser beam characteristics and atmospheric turbulence parameters is proposed and analyzed numerically. The technique is based on utilization of an integral relationship between complex amplitudes of the counterpropagating optical waves known as overlapping integral or interference metric, whose value is preserved along the propagation path. It is shown that the interference metric can be directly measured using the proposed TIL sensing system composed of a single-mode fiber-based optical transceiver and a remotely located retro-target. The measured signal allows retrieval of key beam and atmospheric turbulence characteristics including scintillation index and the path-integrated refractive index structure parameter.

  11. Exoplanet atmospheres physical processes

    CERN Document Server

    Seager, Sara

    2010-01-01

    Over the past twenty years, astronomers have identified hundreds of extrasolar planets--planets orbiting stars other than the sun. Recent research in this burgeoning field has made it possible to observe and measure the atmospheres of these exoplanets. This is the first textbook to describe the basic physical processes--including radiative transfer, molecular absorption, and chemical processes--common to all planetary atmospheres, as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets. In each chapter, Sara Seager offers a conceptual introdu

  12. Symmetries in atmospheric sciences

    CERN Document Server

    Bihlo, Alexander

    2009-01-01

    Selected applications of symmetry methods in the atmospheric sciences are reviewed briefly. In particular, focus is put on the utilisation of the classical Lie symmetry approach to derive classes of exact solutions from atmospheric models. This is illustrated with the barotropic vorticity equation. Moreover, the possibility for construction of partially-invariant solutions is discussed for this model. A further point is a discussion of using symmetries for relating different classes of differential equations. This is illustrated with the spherical and the potential vorticity equation. Finally, discrete symmetries are used to derive the minimal finite-mode version of the vorticity equation first discussed by E. Lorenz (1960) in a sound mathematical fashion.

  13. The impact of quantum interferences between different J-levels on scattering polarization in spectral lines

    CERN Document Server

    Belluzzi, Luca

    2011-01-01

    The spectral line polarization produced by optically pumped atoms contains a wealth of information on the thermal and magnetic structure of a variety of astrophysical plasmas, including that of the solar atmosphere. A correct decoding of such information from the observed Stokes profiles requires a clear understanding of the effects that radiatively induced quantum interferences (or coherences) between pairs of magnetic sublevels produce on these observables, in the absence and in the presence of magnetic fields of arbitrary strength. Here we present a detailed theoretical investigation on the role of coherences between pairs of sublevels pertaining to different fine-structure J-levels, clarifying when they can be neglected for facilitating the modeling of the linear polarization produced by scattering processes in spectral lines. To this end, we apply the quantum theory of spectral line polarization and calculate the linear polarization patterns of the radiation scattered at 90 degrees by a slab of stellar a...

  14. Cooperation for Interference Management: A GDoF Perspective

    KAUST Repository

    Gherekhloo, Soheil

    2016-10-13

    The impact of cooperation on interference management is investigated by studying an elemental wireless network, the so-called symmetric interference relay channel (IRC), from a generalized degrees of freedom (GDoF) perspective. This is motivated by the fact that the deployment of relays is considered as a remedy to overcome the bottleneck of current systems in terms of achievable rates. The focus of this paper is on the regime in which the interference link is weaker than the source-relay link in the IRC. Our approach toward studying the GDoF goes through the capacity analysis of the linear deterministic IRC (LD-IRC). New upper bounds on the sum capacity of the LD-IRC based on genie-aided approaches are established. These upper bounds together with some existing upper bounds are achieved by using four novel transmission schemes. Extending the upper bounds and the transmission schemes to the Gaussian case, the GDoF of the Gaussian IRC is characterized for the aforementioned regime. This completes the GDoF results available in the literature for the symmetric GDoF. It turns out that even if the incoming and outgoing links of the relay are both weaker than the desired channel, involving a relay can increase the GDoF. Interestingly, utilizing the relay in this case can increase the slope of the GDoF from -2 [in the interference channel (IC)] to -1 or 0. This shrinks the regime where ignoring the interference by treating it as noise is optimal. Furthermore, the analysis shows that if the relay ingoing and outgoing links are sufficiently strong, the relay is able to neutralize the interference completely. In this case, the bottleneck of the transmission will be the interference links, and hence, the GDoF increases if the interference link gets stronger. It is shown that in the strong interference regime, in contrast to the IC, the GDoF can be a monotonically decreasing function of the interference level. © 1963-2012 IEEE.

  15. The quantum interference effects in the Sc II 4247 $\\AA$ line of the Second Solar Spectrum

    CERN Document Server

    Smitha, H N; Stenflo, J O; Bianda, M; Ramelli, R

    2014-01-01

    The Sc II 4247 $\\AA$ line formed in the chromosphere is one of the lines well known, like the Na I D$_2$ and Ba II D$_2$, for its prominent triple peak structure in $Q/I$ and the underlying quantum interference effects governing it. In this paper, we try to study the nature of this triple peak structure using the theory of $F$-state interference including the effects of partial frequency redistribution (PRD) and radiative transfer (RT). We compare our results with the observations taken in a quiet region near the solar limb. In spite of accounting for PRD and RT effects it has not been possible to reproduce the observed triple peak structure in $Q/I$. While the two wing PRD peaks (on either side of central peak) and the near wing continuum can be reproduced, the central peak is completely suppressed by the enhanced depolarization resulting from the hyperfine structure splitting. This suppression remains for all the tested widely different 1D model atmospheres or for any multi-component combinations of them. W...

  16. Intensifying the Atmospheric

    DEFF Research Database (Denmark)

    Liebst, Lasse Suonperä

    2012-01-01

    The phenomenological concept of urban atmospheres is more often applied as an aesthetic description of the metropolitan space as such. This conceptualization is supported in this paper; however, I strive to give the concept a post-phenomenological axial turn. While phenomenology, due to its under...... sufficiently intense. All things considered, the paper should be read as a sociological contribution to theoretically reconstruct the concept of urban atmospheres in the light of spatial morphology.......The phenomenological concept of urban atmospheres is more often applied as an aesthetic description of the metropolitan space as such. This conceptualization is supported in this paper; however, I strive to give the concept a post-phenomenological axial turn. While phenomenology, due to its...... are ‘compressed’ by the spatial morphologies of urban space. In this perspective atmospheres are to be understood as an emergent property that develops when the spatial morphological compression of urban life passes a certain threshold, that is, when the affective rhythm of the urban assemblages becomes...

  17. Exoplanet atmosphere highlights

    Science.gov (United States)

    García Muñoz, A.

    2017-03-01

    In only two decades since the first identification of a planet outside the Solar System,and about one since the pioneering detection of an atmosphere, exoplanet science has established itself as a mature field of astrophysics. As the search of as-of-yet undiscovered planets goes on, the field is steadily expanding its focus from detection only to detection and characterization. The information to be grasped from exoplanet atmospheres provides valuable insight into the formation and evolution of the planets and, in turn, into how unique our Solar System is. Ultimately, a dedicated search for life in these distant worlds will have to deal with the information encoded in their atmospheres. In recent years there has been rapid progress on both the theoretical and observational fronts in the investigation of exoplanet atmospheres. Theorists are predicting the prevailing conditions (temperature, chemical composition, cloud occurrence, energy transport) in these objects' envelopes, and are building the frameworks with which to approach the interpretation of observables. In parallel, observers have consolidated the remote sensing techniques that were utilized during the early years, and are now venturing into techniques that hold great promise for the future. With a number of space missions soon to fly and ground-based telescopes and instruments to be commissioned, all of them conceived during the exoplanet era, the field is set to experience unprecedented progress.

  18. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  19. Modeling of Cometary Atmospheres

    Science.gov (United States)

    Gombosi, Tamas

    2004-01-01

    The NASA supported project 'Modeling of Cometary Atmospheres' has been quite successful in broadening our understanding of the cometary environment. We list peer reviewed publications and conference presentation that have been made as a result of studies performed under this project. Following the list we present details of a selection of the results.

  20. Results from atmospheric neutrinos

    Indian Academy of Sciences (India)

    J G Learned

    2000-07-01

    With the announcement of new evidence for muon neutrino disappearance observed by the super-Kamiokande experiment, the more than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an apparently inescapable fact. The evidence is reviewed, and new indications are presented that the oscillations are probably between muon and tau neutrinos. Implications and future directions are discussed.

  1. Astronomy and Atmospheric Optics

    Science.gov (United States)

    Cowley, Les; Gaina, Alex

    2011-12-01

    The authors discusse the insuccess of the observation of the Total Eclipse of the Moon from 10 december 2011 in Romania and relate them with meteoconditions. Only a very short part of the last penumbral phase was observed, while the inital part and the totality was not observed due to very dense clouds. The change in color and brightness during this phase was signaled. Meanwhile, there is an area of science where clouds are of great use and interest. This area is Atmospheric optics, while the science which study clouds is meteorology. Clouds in combination with Solar and Moon light could give rise to a variety of strange, rare and unobvious phenomena in the atmosphere (sky), sometimes confused with Unidentified Flying Objects (UFO). The importance of meteorology for astronomy and atmospheric optics is underlined and an invitation to astronomers to use unfavourable days for athmospheric observations was sent. The web address of the site by Les Cowley, designed for atmospheric optics phenomena is contained in the text of the entry.

  2. Atmospheric pollution in Lisbon urban atmosphere

    Science.gov (United States)

    Oliveira, C.

    2009-04-01

    Lisbon is the capital city of Portugal with about 565,000 residents in 2008 and a population density of 6,600 inhabitants per square kilometre. Like several other major metropolis, the town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants, a quarter of the overall Portuguese population. Besides their local residents, it is estimated that more than one million citizens come into the Lisbon area every day from the outskirts, leading to elevated traffic densities and intense traffic jams, with important consequences on air pollution levels and obvious negative impacts on human health. Airborne particulate matter limit values are frequently exceeded, making urgent the existence of consistent programs to monitor and help taking measures to control them. Within the Portuguese project PAHLIS (Polycyclic Aromatic Hydrocarbons Contamination in Lisbon Urban Atmosphere) financed by the Portuguese Science Foundation ("Fundação para a Ciência e a Tecnologia"), an aerosol and vapour phase sampling program is being implemented in the city of Lisbon at two selected contrasting zones, namely a typically busy area with intense road traffic and frequent exceedences of the particulate matter standard for the maximum allowable concentration, and a residential quieter area, thus with a cleaner atmosphere characterised as an urban background site. An one month-long sampling campaign was performed during the summer of 2008, where particulate matter was collected in two fractions (coarse 2.5µm

  3. Atmospheric turbulence affects wind turbine nacelle transferfunctions

    Energy Technology Data Exchange (ETDEWEB)

    St. Martin, Clara M.; Lundquist, Julie K.; Clifton, Andrew; Poulos, Gregory S.; Schreck, Scott J.

    2016-12-14

    Despite their potential as a valuable source of individual turbine power performance and turbine array energy production optimization information, nacelle-mounted anemometers have often been neglected because complex flows around the blades and nacelle interfere with their measurements. This work quantitatively explores the accuracy of and potential corrections to nacelle anemometer measurements to determine the degree to which they may be useful when corrected for these complex flows, particularly for calculating annual energy production (AEP) in the absence of other meteorological data. Using upwind meteorological tower measurements along with nacelle-based measurements from a General Electric (GE) 1.5sle model, we calculate empirical nacelle transfer functions (NTFs) and explore how they are impacted by different atmospheric and turbulence parameters. This work provides guidelines for the use of NTFs for deriving useful wind measurements from nacelle-mounted anemometers. Corrections to the nacelle anemometer wind speed measurements can be made with NTFs and used to calculate an AEP that comes within 1 % of an AEP calculated with upwind measurements. We also calculate unique NTFs for different atmospheric conditions defined by temperature stratification as well as turbulence intensity, turbulence kinetic energy, and wind shear. During periods of low stability as defined by the Bulk Richardson number (RB), the nacelle-mounted anemometer underestimates the upwind wind speed more than during periods of high stability at some wind speed bins below rated speed, leading to a more steep NTF during periods of low stability. Similarly, during periods of high turbulence, the nacelle-mounted anemometer underestimates the upwind wind speed more than during periods of low turbulence at most wind bins between cut-in and rated wind speed. Based on these results, we suggest different NTFs be calculated for different regimes of atmospheric stability

  4. Interference Control for Cognitive Network with High Mobility

    Directory of Open Access Journals (Sweden)

    Yuanxuan Li

    2013-01-01

    Full Text Available Interference control (IC between the secondary system and the primary system is an important issue for underlay cognitive radio network (CRN. The secondary system should limit the interference power to primary system by adjusting its transmission power. Many relevant works have been done based on the assumption of the quasistatic channel which is not suitable for the fast time-varying fading channel; the performance of IC in underlay CRN will become worse when the channel varies fast. This paper studies the IC issue in high mobility environment. By considering the channel state information (CSI outdatedness, a short frame structure scheme and a mean interference power constraint scheme are proposed to reduce the influence of CSI outdatedness on IC performance. Furthermore, by considering the channel estimation error, a spherical error region model based robust IC scheme is designed as well. The proposed IC schemes of the secondary system are converted to the power allocation problems, and then they are formulated to optimization problem whose objects are to maximize the capacity of the secondary system with the interference constraints. The above optimization problems are solved by the water-filling style method. The simulation results show that the proposed IC schemes can effectively control the interference power to the primary system.

  5. Memory Interference as a Determinant of Language Comprehension.

    Science.gov (United States)

    Van Dyke, Julie A; Johns, Clinton L

    2012-04-01

    The parameters of the human memory system constrain the operation of language comprehension processes. In the memory literature, both decay and interference have been proposed as causes of forgetting; however, while there is a long history of research establishing the nature of interference effects in memory, the effects of decay are much more poorly supported. Nevertheless, research investigating the limitations of the human sentence processing mechanism typically focus on decay-based explanations, emphasizing the role of capacity, while the role of interference has received comparatively little attention. This paper reviews both accounts of difficulty in language comprehension by drawing direct connections to research in the memory domain. Capacity-based accounts are found to be untenable, diverging substantially from what is known about the operation of the human memory system. In contrast, recent research investigating comprehension difficulty using a retrieval-interference paradigm is shown to be wholly consistent with both behavioral and neuropsychological memory phenomena. The implications of adopting a retrieval-interference approach to investigating individual variation in language comprehension are discussed.

  6. Unraveling cell processes: interference imaging interwoven with data analysis

    DEFF Research Database (Denmark)

    Brazhe, Nadezda; Brazhe, Alexey; Pavlov, A N;

    2006-01-01

    The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution of hemoglo......The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution...... properties differ from cell type to cell type and depend on the cellular compartment. Our results suggest that low frequency variations (0.1-0.6 Hz) result from plasma membrane processes and that higher frequency variations (20-26 Hz) are related to the movement of vesicles. Using double-wavelet analysis, we...... study the modulation of the 1 Hz rhythm in neurons and reveal its changes under depolarization and hyperpolarization of the plasma membrane. We conclude that interference microscopy combined with wavelet analysis is a useful technique for non-invasive cell studies, cell visualization, and investigation...

  7. Interference Management for LTE Femtocell System Using Power Control

    Science.gov (United States)

    Cho, Kyong-Tak; Kim, Junsik; Jeon, Gwangil; Ryu, Byunghan; Park, Namhoon

    Since femtocells are deployed in a two tier cellular network, along with macrocells operating on the same channel, interference between them limits the overall performance of the network. Without any control of the femtocell operation, pre-deployed macrocells will experience severe interference, which is not consistent with the current femtocell deployment principle. In this paper, to resolve this problem, a mathematical framework that optimizes the downlink transmission power of femtocells is formulated. Based on the formulated framework, we derive the optimal value of the transmission power so that the transmission affects the pre-deployed macrocell's downlink performance at a minimum scale, while providing sufficient Quality of Service (QoS) to its served users. Furthermore, to reduce the complexity of the power control process, we propose an Interference Estimation scheme which approximates the interference levels between different pairs of macrocell and femtocell base stations. The feasibility of this estimation process is shown by deriving the lower and upper bound of the estimation error. Through simulations, compared to no power control, we show that our proposed method provides a 17.64% reduction in macro user's outage probability, 5.9dB decrease of interference on cell-edge macrocell users, and a 1.41 times increase in average user throughput.

  8. Risk of overestimation of urinary cadmium concentrations: interference from molybdenum

    Directory of Open Access Journals (Sweden)

    Cañas A.I.

    2013-04-01

    Full Text Available We show here that the selection of analytical method is critical when measuring low levels of cadmium in human urine. Cadmium is today usually analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS, which has a higher sensitivity than Atomic Absorption Spectroscopy (AAS. ICP-MS cadmium measurements show interference from tin (114Sn and molybdenum oxides, which can result in an overestimation of cadmium levels. The 114Sn interference is stable and can be mathematically corrected. Molybdenum concentrations in urine are variable and different from individual to individual. We have estimated the degree of error which molybdenum interference introduces in the measurement of cadmium in urine by conventional ICP-MS. 268 urine samples from mothers and their children were measured. Removal of the molybdenum oxide interference (DRC-ICP-MS method reduced urinary cadmium concentrations significantly (47.8%. The urinary molybdenum concentration in children was higher than in their mothers, resulting in greater overestimation. Our results clearly show that the DRC method is essential for reliable measurements of urinary cadmium concentrations, particularly in children. Furthermore, care should be taken when comparing Human Biomonitoring data for cadmium in urine and attention should be paid to which analytical method has been used (e.g. AAS and ICP-Ms, and especially if the measurements have been corrected for molybdenum interference.

  9. Interference Assembly and Fretting Wear Analysis of Hollow Shaft

    Directory of Open Access Journals (Sweden)

    Chuanjun Han

    2014-01-01

    Full Text Available Fretting damage phenomenon often appears in the interference fit assembly. The finite element model of hollow shaft and shaft sleeve was established, and the equivalent stress and contact stress were computed after interference assembly. The assembly body of hollow shaft and shaft sleeve was in whirling bending load, and the contact status (sticking, sliding, and opening and the distribution of stress along one typical contact line were computed under different loads, interferences, hollow degrees, friction coefficient, and wear quantity. Judgment formula of contact state was fixed by introducing the corrected coefficient k. The computation results showed that the “edge effect” appears in the contact surface after interference fit. The size of slip zone is unchanged along with the increase of bending load. The greater the interference value, the bigger the wear range. The hollow degree does not influence the size of stick zone but controls the position of the junction point of slip-open. Tangential contact stress increases with the friction coefficient, which has a little effect on normal contact stress. The relationship between open size and wear capacity is approximately linear.

  10. Clustering-based interference management in densely deployed femtocell networks

    Directory of Open Access Journals (Sweden)

    Jingyi Dai

    2016-11-01

    Full Text Available Deploying femtocells underlaying macrocells is a promising way to improve the capacity and enhance the coverage of a cellular system. However, densely deployed femtocells in urban area also give rise to intra-tier interference and cross-tier issue that should be addressed properly in order to acquire the expected performance gain. In this paper, we propose an interference management scheme based on joint clustering and resource allocation for two-tier Orthogonal Frequency Division Multiplexing (OFDM-based femtocell networks. We formulate an optimization task with the objective of maximizing the sum throughput of the femtocell users (FUs under the consideration of intra-tier interference mitigation, while controlling the interference to the macrocell user (MU under its bearable threshold. The formulation problem is addressed by a two-stage procedure: femtocells clustering and resource allocation. First, disjoint femtocell clusters with dynamic sizes and numbers are generated to minimize intra-tier interference. Then each cluster is taken as a resource allocation unit to share all subchannels, followed by a fast algorithm to distribute power among these subchannels. Simulation results show that our proposed schemes can improve the throughput of the FUs with acceptable complexity.

  11. Interference-Robust Transmission in Wireless Sensor Networks.

    Science.gov (United States)

    Han, Jin-Seok; Lee, Yong-Hwan

    2016-11-14

    Low-power wireless sensor networks (WSNs) operating in unlicensed spectrum bands may seriously suffer from interference from other coexisting radio systems, such as IEEE 802.11 wireless local area networks. In this paper, we consider the improvement of the transmission performance of low-power WSNs by adjusting the transmission rate and the payload size in response to the change of co-channel interference. We estimate the probability of transmission failure and the data throughput and then determine the payload size to maximize the throughput performance. We investigate that the transmission time maximizing the normalized throughput is not much affected by the transmission rate, but rather by the interference condition. We adjust the transmission rate and the transmission time in response to the change of the channel and interference condition, respectively. Finally, we verify the performance of the proposed scheme by computer simulation. The simulation results show that the proposed scheme significantly improves data throughput compared with conventional schemes while preserving energy efficiency even in the presence of interference.

  12. Interference suppression capabilities of smart cognitive-femto networks (SCFN)

    KAUST Repository

    Shakir, Muhammad

    2013-01-01

    Cognitive Radios are considered a standard part of future heterogeneous mobile network architectures. In this chapter, a two tier heterogeneous network with multiple Radio Access Technologies (RATs) is considered, namely (1) the secondary network, which comprises of Cognitive-Femto BS (CFBS), and (2) the macrocell network, which is considered a primary network. By exploiting the cooperation among the CFBS, the multiple CFBS can be considered a single base station with multiple geographically dispersed antennas, which can reduce the interference levels by directing the main beam toward the desired femtocell mobile user. The resultant network is referred to as Smart Cognitive-Femto Network (SCFN). In order to determine the effectiveness of the proposed smart network, the interference rejection capabilities of the SCFN is studied. It has been shown that the smart network offers significant performance improvements in interference suppression and Signal to Interference Ratio (SIR) and may be considered a promising solution to the interference management problems in future heterogeneous networks. © 2013, IGI Global.

  13. RNA Interference in the Age of CRISPR: Will CRISPR Interfere with RNAi?

    Directory of Open Access Journals (Sweden)

    Unnikrishnan Unniyampurath

    2016-02-01

    Full Text Available The recent emergence of multiple technologies for modifying gene structure has revolutionized mammalian biomedical research and enhanced the promises of gene therapy. Over the past decade, RNA interference (RNAi based technologies widely dominated various research applications involving experimental modulation of gene expression at the post-transcriptional level. Recently, a new gene editing technology, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR and the CRISPR-associated protein 9 (Cas9 (CRISPR/Cas9 system, has received unprecedented acceptance in the scientific community for a variety of genetic applications. Unlike RNAi, the CRISPR/Cas9 system is bestowed with the ability to introduce heritable precision insertions and deletions in the eukaryotic genome. The combination of popularity and superior capabilities of CRISPR/Cas9 system raises the possibility that this technology may occupy the roles currently served by RNAi and may even make RNAi obsolete. We performed a comparative analysis of the technical aspects and applications of the CRISPR/Cas9 system and RNAi in mammalian systems, with the purpose of charting out a predictive picture on whether the CRISPR/Cas9 system will eclipse the existence and future of RNAi. The conclusion drawn from this analysis is that RNAi will still occupy specific domains of biomedical research and clinical applications, under the current state of development of these technologies. However, further improvements in CRISPR/Cas9 based technology may ultimately enable it to dominate RNAi in the long term.

  14. RNA Interference in the Age of CRISPR: Will CRISPR Interfere with RNAi?

    Science.gov (United States)

    Unniyampurath, Unnikrishnan; Pilankatta, Rajendra; Krishnan, Manoj N

    2016-02-26

    The recent emergence of multiple technologies for modifying gene structure has revolutionized mammalian biomedical research and enhanced the promises of gene therapy. Over the past decade, RNA interference (RNAi) based technologies widely dominated various research applications involving experimental modulation of gene expression at the post-transcriptional level. Recently, a new gene editing technology, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and the CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) system, has received unprecedented acceptance in the scientific community for a variety of genetic applications. Unlike RNAi, the CRISPR/Cas9 system is bestowed with the ability to introduce heritable precision insertions and deletions in the eukaryotic genome. The combination of popularity and superior capabilities of CRISPR/Cas9 system raises the possibility that this technology may occupy the roles currently served by RNAi and may even make RNAi obsolete. We performed a comparative analysis of the technical aspects and applications of the CRISPR/Cas9 system and RNAi in mammalian systems, with the purpose of charting out a predictive picture on whether the CRISPR/Cas9 system will eclipse the existence and future of RNAi. The conclusion drawn from this analysis is that RNAi will still occupy specific domains of biomedical research and clinical applications, under the current state of development of these technologies. However, further improvements in CRISPR/Cas9 based technology may ultimately enable it to dominate RNAi in the long term.

  15. RNA interference and small interference RNA%RNA干涉和小干涉RNA

    Institute of Scientific and Technical Information of China (English)

    张芹; 王勇; 钱凯先

    2005-01-01

    RNA干涉(RNA interference.RNAi)可以抑制诸多真核基因的表达,小干涉RNA(small intmference RNA,siRNA)是RNA干涉的引发物,不同的siRNA可以引导不同水平的RNA干涉,不同种细胞中siRNA的寡核苷酸链的性质也有很大的不同.非编码RNA中的微小RNA(micnoRNA,miRNA)与siRNA在结构及作用方式等方面有很多区别和联系.RNAi的作用机制大致有两种:在Drosophila中的一般作用模式和在C.elegans中的扩大作用模式.利用RNA干涉技术可以通过抑制基因的表达来研究其功能;RNA干涉作为基因治疗的工具,在肝炎和AIDS的治疗过程中有一定的作用.RNAi的高特异性、高效性、放大效应和无细胞特异性等特点在科研中得到了广泛的应用.

  16. Influence of Decoherence on Interference Between Two Bose-Einstein Condensates

    Institute of Scientific and Technical Information of China (English)

    ZENG Ai-Hua; KUANG Le-Man

    2004-01-01

    The influence of decoherence on interference between two trapped Bose-Einstein condensates with arbitrary initial states is studied. Analytic expressions of the intensity and visibility of the interference pattern are found. It is shown that the decoherence weakens the interference intensity and decreases the visibility of the interference pattern.

  17. Fourth-Order Interference in Femtosecond Spontaneous Parametric Down-Conversion

    Institute of Scientific and Technical Information of China (English)

    JIANG Yun-Kun; SHI Bao-Sen; LI Jian; FAN Xiao-Feng; GUO Guang-Can

    2000-01-01

    We report a fourth-order interference experiment in which pairs of photons are produced in spontaneous parametric down-conversion pumped by femtosecond pulses interfere in a Hong-Ou-Mandel interferometer. The visibilityof the interference is (64±4)%, exceeding the bound of 50% predicted by classical interference theory.

  18. Atmospheric lepton fluxes

    Directory of Open Access Journals (Sweden)

    Gaisser Thomas K.

    2015-01-01

    Full Text Available This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric νμ and νe are discussed, along with the implications of the muon charge ratio for the νµ / ν̅µ ratio. Methods to account for effects of the knee in the primary cosmic-ray spectrum and the energy-dependence of hadronic interactions on the neutrino fluxes are discussed and illustrated in the context of recent results from IceCube. A simple numerical/analytic method is proposed for systematic investigation of uncertainties in neutrino fluxes arising from uncertainties in the primary cosmic-ray spectrum/composition and hadronic interactions.

  19. Dreaming of atmospheres

    CERN Document Server

    Waldmann, I P

    2015-01-01

    Here we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrievals of exoplanetary atmospheres frequently requires the preselection of molecular/atomic opacities to be defined by the user. In the era of open-source, automated and self-sufficient retrieval algorithms, manual input should be avoided. User dependent input could, in worst case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is based on deep belief neural (DBN) networks trained to accurately recognise molecular signatures for a wide range of planets, atmospheric thermal profiles and compositions. Reconstructions of the learned features, also referred to as `dreams' of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work towards retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from curre...

  20. PERSPECTIVE: On the verge of dangerous anthropogenic interference with the climate system?

    Science.gov (United States)

    Kriegler, Elmar

    2007-03-01

    The recent publication of the summary for policy makers by Working Group I of the Intergovernmental Panel on Climate Change (IPCC) [1] has injected a renewed sense of urgency to address climate change. It is therefore timely to review the notion of preventing 'dangerous anthropogenic interference with the climate system' as put forward in the United Nations Framework Convention on Climate Change (UNFCCC). The article by Danny Harvey in this issue [2] offers a fresh perspective by rephrasing the concept of 'dangerous interference' as a problem of risk assessment. As Harvey points out, identification of 'dangerous interference' does not require us to know with certainty that future climate change will be dangerous—an impossible task given that our knowledge about future climate change includes uncertainty. Rather, it requires the assertion that interference would lead to a significant probability of dangerous climate change beyond some risk tolerance, and therefore would pose an unacceptable risk. In his article [2], Harvey puts this idea into operation by presenting a back-of-the-envelope calculation to identify allowable CO2 concentrations under uncertainty about climate sensitivity to anthropogenic forcing and the location of a temperature threshold beyond which dangerous climate change will occur. Conditional on his assumptions, Harvey delivers an interesting result. With the current atmospheric CO2 concentration exceeding 380 ppm, a forcing contribution from other greenhouse gases adding an approximate 100 110 ppm CO2 equivalent on top of it, and a global dimming effect of aerosols that roughly compensates for this contribution (albeit still subject to considerable uncertainty) ([1], figures SPM-1 and 2), we are on the verge of or even committed to dangerous interference with the climate system if we (1) set the risk tolerance for experiencing dangerous climate change to 1% and (2) allocate at least 5% probability to the belief that climate sensitivity is 4