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Sample records for water resistor divider

  1. Breakdown voltage of metal-oxide resistors in liquid argon

    International Nuclear Information System (INIS)

    We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131 kV pulses, the limit of the test setup

  2. For current viewing resistor loads

    Science.gov (United States)

    Lyons, Gregory R. (Tijeras, NM); Hass, Jay B. (Lee's Summit, MO)

    2011-04-19

    The invention comprises a terminal unit for a flat cable comprising a BNC-PCB connector having a pin for electrically contacting one or more conducting elements of a flat cable, and a current viewing resistor having an opening through which the pin extends and having a resistor face that abuts a connector face of the BNC-PCB connector, wherein the device is a terminal unit for the flat cable.

  3. Resistor network for linearity check of voltage ratio meters by combinatorial calibration technique

    Science.gov (United States)

    Hiti, M.

    2015-05-01

    This article describes a resistor network for linearity verification of voltage ratio-indicating instruments. The network is based on a resistive divider with low variation of input and output resistance. To compensate for the output resistance change due to a selection of various output ratios, a switched variable compensating resistor network is added to the output leads of the voltage divider. It limits the variation of output resistance to pressure. The circuit is suitable for verifying the linearity of voltage ratio measuring instruments by using a combinatorial calibration technique without the need to calibrate the resistor network. Results are shown for the linearity check of a high-precision strain gauge amplifier.

  4. Farey Sequences and Resistor Networks

    Indian Academy of Sciences (India)

    Sameen Ahmed Khan

    2012-05-01

    In this article, we employ the Farey sequence and Fibonacci numbers to establish strict upper and lower bounds for the order of the set of equivalent resistances for a circuit constructed from equal resistors combined in series and in parallel. The method is applicable for networks involving bridge and non-planar circuits.

  5. Remote Experiments in Resistor Measurement

    Directory of Open Access Journals (Sweden)

    Popescu Viorel

    2009-10-01

    Full Text Available The paper describes blended learningapproach to teaching resistor measurement. It is basedon “Learning by Doing” paradigm: interacticesimulation, laboratory plants, real experimentsaccessed by Web Publishing Tools under LabVIEW.Studying and experimenting access is opened for 24hours a day, 7 days a week under Moodle bookingsystem.

  6. Remote Experiments in Resistor Measurement

    OpenAIRE

    Popescu Viorel; B?b?i?? Mircea; Popovici Adrian; Lascu Dan; Negoi?escu Dan; Lascu Mihaela

    2009-01-01

    The paper describes blended learningapproach to teaching resistor measurement. It is basedon “Learning by Doing” paradigm: interacticesimulation, laboratory plants, real experimentsaccessed by Web Publishing Tools under LabVIEW.Studying and experimenting access is opened for 24hours a day, 7 days a week under Moodle bookingsystem.

  7. Power Divider

    OpenAIRE

    Chen, Yu Christine; Dhople, Sairaj

    2015-01-01

    This paper derives analytical closed-form expressions that uncover the contributions of nodal active- and reactive-power injections to the active- and reactive-power flows on transmission lines in an AC electrical network. Paying due homage to current- and voltage-divider laws that are similar in spirit, we baptize these as the power divider laws. Derived from a circuit-theoretic examination of AC power-flow expressions, the constitution of the power divider laws reflects th...

  8. DIGITAL DIVIDE

    OpenAIRE

    PRAVEENKUMAR. KUMBARGOUDAR

    2013-01-01

    Digital Divide may also be called as “Information and Technology gap”. In general terms, it is the gap between those who can effectively use new information and communication tools, such as the internet, and those who cannot. The digital divide becomes challenge for the development of digital libraries in India. Because the different factors such as Illiteracy, Poverty, Computer illiteracy, lack of widespread telecommunication facilities, shortage of power supply etc. created the digital divi...

  9. Software Development in the Water Sciences: a view from the divide (Invited)

    Science.gov (United States)

    Miles, B.; Band, L. E.

    2013-12-01

    While training in statistical methods is an important part of many earth scientists' training, these scientists often learn the bulk of their software development skills in an ad hoc, just-in-time manner. Yet to carry out contemporary research scientists are spending more and more time developing software. Here I present perspectives - as an earth sciences graduate student with professional software engineering experience - on the challenges scientists face adopting software engineering practices, with an emphasis on areas of the science software development lifecycle that could benefit most from improved engineering. This work builds on experience gained as part of the NSF-funded Water Science Software Institute (WSSI) conceptualization award (NSF Award # 1216817). Throughout 2013, the WSSI team held a series of software scoping and development sprints with the goals of: (1) adding features to better model green infrastructure within the Regional Hydro-Ecological Simulation System (RHESSys); and (2) infusing test-driven agile software development practices into the processes employed by the RHESSys team. The goal of efforts such as the WSSI is to ensure that investments by current and future scientists in software engineering training will enable transformative science by improving both scientific reproducibility and researcher productivity. Experience with the WSSI indicates: (1) the potential for achieving this goal; and (2) while scientists are willing to adopt some software engineering practices, transformative science will require continued collaboration between domain scientists and cyberinfrastructure experts for the foreseeable future.

  10. Continental divide

    International Nuclear Information System (INIS)

    The historical precedents to the idea of continent-wide diversion of water in North America are reviewed, starting from early perceptions of continental drainage and the era of canal building that reached its peak in the mid-1800s. The attitude that natural landscapes can be rearranged to suit human needs has persisted from that era with the proposal for continent-wide water diversion megaprojects, many involving the movement of water from Canada to the southwestern USA. Over 50 water diversions exist in Canada, with a total diverted flow of 4,400 m3/s. The density of interconnected and almost-connected lakes and rivers has favored such diversions. Of these diversions, 95% of their storage capacity and 96% of their flow is for hydroelectric power generation. The number of diversions in the USA is similar but water volumes are only a sixth of those in Canada, and the water is mainly used for irrigation or water supply. Experience in both countries shows that diversions are contained by political boundaries. No large-scale diversion of fresh water across the international boundary has received any government support, and no significant change in this policy is anticipated. In the water-short areas of the USA, conservation and reallocation of water resources are receiving priority. 19 refs., 2 figs., 2 tabs

  11. Effect of a divided wetwell on heat removal capability of the water wall type passive capability of the water wall type passive containment cooling system

    International Nuclear Information System (INIS)

    A water wall type containment cooling system, which has a colling pool outside the suppression pool, is one of the passive containment cooling systems (PCCSs). To improve its heat removel capability, we have proposed a divided wetwell (gas phase space in the suppression chamber), which separates the wetwell space into a high steam partial pressure region (first wetwell) and high noncondensable gas partial pressure region (second wetwell). We experimentally examined the thermal hydraulic behavior of the wall type PCCS which applies the divided wetwell. By cooling the second wetwell and condensing the steams which flowed from the first wetwell into the second wetwell, noncondensable gas in the first wetwell was discharged to the second wetwell. In the first wetwell, the saturated steam pressure increased. After the noncondensable gas was fully discharged to the second wetwell, the first wetwell temperature came within 1degC of the suppression pool surface temperature. Therefore, attainable temperatures of the first wetwell and the suppression pool water increased for the same pressure of the primary containment vessel. Consequently, the time-integrated released heat to the outer pool was 70% larger than the non-divided case due to increase of the temperature difference between the suppression pool and outer pool. (author)

  12. Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks

    International Nuclear Information System (INIS)

    This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of ?1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm3 liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by ?0.4 C which produces a 0.7% change in resistance. The typical cooling rate is ?0.4 C per minute which results in ?0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic is minimized while still offering the desired low temperature coefficient of resistance compared to sodium thiosulfate. The characterization experiments and comparison with the sodium thiosulfate liquid resistors will be fully discussed and the final design described.

  13. A comprehensive study of polysilicon resistors for CMOS ULSI applications

    Science.gov (United States)

    Chuang, Hung-Ming; Thei, Kong-Beng; Tsai, Sheng-Fu; Lu, Chun-Tsen; Liao, Xin-Da; Lee, Kuan-Ming; Chen, Hon-Rung; Liu, Wen-Chau

    2003-04-01

    The characteristics of polysilicon resistors for CMOS ULSI applications have been investigated. Based on the presented sub-quarter micron CMOS borderless contact, both n + and p + polysilicon resistors with Ti- and Co-silicide self-aligned process are used at the ends of each resistor. A simple and useful model is proposed to analyse and calculate some important parameters of polysilicon resistors including electrical delta W(? W), interface resistance Rinterface, and pure sheet resistance Rpure. Furthermore, the characteristics of voltage-coefficient resistor, temperature-coefficient resistor, and resistor mismatching are also studied. An interesting sine-wave voltage-dependent characteristic due to the strong relation to the Rinterface has been modelled in this paper. This approach can substantially help engineers in designing and fabricating the precise polysilicon resistors in sub-quarter micron CMOS ULSI technology.

  14. Stochastic Resonance Induced by Dichotomous Resistor in an Electric Circuit

    International Nuclear Information System (INIS)

    An electric circuit with dichotomous resistor is investigated. It is shown that the amplitude of the average electric current washing the resistor represents the phenomenon of stochastic resonance, which is the response as a function of the correlation time of the dichotomous resistor.

  15. Study of thin-film resistor resistance error

    Directory of Open Access Journals (Sweden)

    Spirin V. G.

    2009-10-01

    Full Text Available A relationship between a thin-film resistor resistance error and mask misalignment with a substrate conductive layer at the second photolithography stage for a thin-film resistor design in which the resistive element does not overlap conductor pads is studied. The error value is at a maximum when the resistor aspect ratio is equal to 1.0.

  16. Rational and irrational numbers from unit resistors

    International Nuclear Information System (INIS)

    We address the problem of constructing a network of unit resistors such that it enables the retrieval of an arbitrary value of equivalent resistance. In particular, we employ the notion of continued fractions to construct a ladder network by which we can easily obtain any fractional value resistance. In addition, since any irrational number is associated with an infinite continued fraction, we discuss the convergence of the equivalent resistance of an infinite resistive ladder and various aspects concerning the approximations of arbitrary numbers attained by adding additional resistors successively to the network. The presented methods can be easily implemented in an educational laboratory and offer an interesting addition to the topic of Ohm’s law. (paper)

  17. Regulating resistor and interruptor for the toroidal field system on the TEXT Tokamak development tests

    International Nuclear Information System (INIS)

    Tests on two prototype electrolytic resistors-interrupters demonstrated the practicality of this approach to interrupting and regulating high DC currents of modest voltage as they occur, for instance, in the toroidal field circuit of a tokamak fed by homopolar machines. NaOH in water solution is suitable as an electrolyte in conjunction with mild steel electrodes. Suitable materials for insulation, gaskets, etc. were established and other materials which are in common engineering usage were found to be incompatible with this particular application. The relationship given in formula together with consideration of average heating per shot permits to dimension the resistors in a conservative manner and has been used for the basic design of the TEXT resistors

  18. Precision resistors for AC and DC

    International Nuclear Information System (INIS)

    Precision resistors of special construction with nominal values of 1000 ? are described. They are used in the PTB as AC-DC transfer standards for the determination of the Sl-unit Ohm based on the Sl-unit Farad realized by the method of Thompson and Lampard. The difference between the resistance values at AC and at DC are calculated with a relative uncertainty (1 sigma) of +- 0.6 x 10-9. (orig.)

  19. Braking Resistor Scheme for Transient Stability Improvement

    OpenAIRE

    Saeed Abazari

    2007-01-01

    One of the most important problems in power systems design is increasing the damping of the swing amplitude and also to increase the critical time in transient stability. One of the best techniques is to use resistor braking. However, their performance in power systems, duration of their activity and their place of installation are of great importance. In this paper by using of some of devices in power electronics and by precies modeling of the network and optimal controller is designed which...

  20. Correlated percolation and the correlated resistor network

    OpenAIRE

    Bastiaansen, Paul J. M.; Knops, Hubert J. F.

    1996-01-01

    We present some exact results on percolation properties of the Ising model, when the range of the percolating bonds is larger than nearest-neighbors. We show that for a percolation range to next-nearest neighbors the percolation threshold Tp is still equal to the Ising critical temperature Tc, and present the phase diagram for this type of percolation. In addition, we present Monte Carlo calculations of the finite size behavior of the correlated resistor network defined on t...

  1. Variable thermal resistor based on self-powered Peltier effect

    International Nuclear Information System (INIS)

    Heat flow through a thermoelectric material or device can be varied by an electrical resistor connected in parallel to it. This phenomenon is exploited to design a novel thermal component-variable thermal resistor. The theoretical background to this novel application is provided and an experimental result to demonstrate its feasibility is reported. (fast track communication)

  2. Spectral fluctuation dividing for efficient wavenumber selection: application to estimation of water and drug content in granules using near infrared spectroscopy.

    Science.gov (United States)

    Miyano, Takuya; Kano, Manabu; Tanabe, Hideaki; Nakagawa, Hiroshi; Watanabe, Tomoyuki; Minami, Hidemi

    2014-11-20

    In process analytical technology (PAT) based on near infrared (NIR) spectroscopy, wavenumber selection is crucial to develop an accurate and robust calibration model. The present research proposes new efficient spectral dividing and wavenumber selection methods to significantly reduce the computational load required by conventional wavenumber selection methods such as interval partial least squares (iPLS). The proposed method, named spectral fluctuation dividing (SFD), divides a whole spectrum into multiple spectral intervals at local minimum points of the spectral fluctuation profile, which consists of the standard deviation of absorbance at each wavenumber in a calibration set. SFD is combined with PLS (SFD-PLS) to select the spectral intervals at which input variables have significant influence on a target response. The usefulness of SFD-PLS was demonstrated through its application to the problems of estimating water and drug content in granules. PLS models based on SFD-PLS achieved higher estimation accuracy than those based on conventional methods including iPLS, PLS-beta, and variable influence on projection (VIP). In addition, SFD-PLS was more than 10 times faster than the conventional variable selection methods including PLS-beta and VIP; in particular, SFD-PLS was more than 25 times faster than iPLS. Consequently, the proposed SFD-PLS is a promising wavenumber selection method. PMID:25218183

  3. Correlated percolation and the correlated resistor network

    CERN Document Server

    Bastiaansen, P J M; Bastiaansen, Paul J. M.; Knops, Hubert J. F.

    1996-01-01

    We present some exact results on percolation properties of the Ising model, when the range of the percolating bonds is larger than nearest-neighbors. We show that for a percolation range to next-nearest neighbors the percolation threshold Tp is still equal to the Ising critical temperature Tc, and present the phase diagram for this type of percolation. In addition, we present Monte Carlo calculations of the finite size behavior of the correlated resistor network defined on the Ising model. The thermal exponent t of the conductivity that follows from it is found to be t = 0.2000 +- 0.0007. We observe no corrections to scaling in its finite size behavior.

  4. Bifurcation diagrams in MOS-NDR frequency divider circuits

    OpenAIRE

    Núñez, Juan; Avedillo, M. J.; Quintana, J. M.

    2012-01-01

    The behavior of a circuit able to implement frequency division is studied. It is composed of a block with an I-V characteristic exhibiting Negative Differential Resistance (NDR) built from MOS transistors plus an inductor and a resistor. Frequency division is obtained from the period adding sequences which appear in its bifurcation diagram. The analyzed circuit is an “all MOS” version of one previously reported which uses Resonant Tunneling Diodes (RTDs). The results show that the dividing ra...

  5. Continental Divide Trail

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This shapefile was created to show the proximity of the Continental Divide to the Continental Divide National Scenic Trail in New Mexico. This work was done as part...

  6. Room-temperature antiferromagnetic memory resistor

    Science.gov (United States)

    Marti, X.; Fina, I.; Frontera, C.; Liu, Jian; Wadley, P.; He, Q.; Paull, R. J.; Clarkson, J. D.; Kudrnovský, J.; Turek, I.; Kuneš, J.; Yi, D.; Chu, J.-H.; Nelson, C. T.; You, L.; Arenholz, E.; Salahuddin, S.; Fontcuberta, J.; Jungwirth, T.; Ramesh, R.

    2014-04-01

    The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.

  7. Free-standing silicon micro machined resistors from (110) substrate

    International Nuclear Information System (INIS)

    A simple process to obtain silicon planes released from the substrate and provided with large area pads for ohmic contacts is described. Resistors 500 ?m long with a 40 ?m x 1 ?m cross section were obtained. Resistance measurements showed that the current flows in a reduced cross section, probably owing to the presence of a superficial depletion layer. Preliminary magnetoresistance measurements are presented. Reduction of the resistor cross section can be obtained by thermal oxidation

  8. Dynamic Systems Model for Filamentary Mem-Resistors

    OpenAIRE

    Mouttet, Blaise

    2011-01-01

    A dynamic systems model is proposed describing memory resistors which include a filament conductive bridge. In this model the system state is defined by both a dynamic tunneling barrier (associated with the filament-electrode gap) and a dynamic Schottky barrier (associated with the electron depletion width surrounding the filament-electrode gap). A general model is formulated which may be applicable to many different forms of memory resistor materials. The frequency response...

  9. Burden resistor selection in current transformers for low power applications

    OpenAIRE

    Conesa Roca, Alfons; Bargalló Perpiñá, Ramón; Velasco Quesada, Guillermo; Román Lumbreras, Manuel

    2014-01-01

    In order to sense AC current with electric isolation in high frequency switching power converters the most simple and low cost solution is to consider a current transformer with a burden resistor. But burden resistor selection is not a simple task because involves a lot of considerations that affect the output voltage and its signal-to-noise ratio and the bandwidth of the measure. In this paper, considering the basic equations of the transformer and applying the Laplace Transformation is obta...

  10. Experimental Research on Properties of Materials of Grounding Resistor

    OpenAIRE

    He Da-Jiang; Xiao-Jing; Yang Heng-Ling; Qu-Jun; Liu Liang-Yuan

    2013-01-01

    In this study, we have a experimental research on properties of materials of grounding resistor. Experiment test of the grounding resistor in the state of analog ground fault have been done, the performance parameters on the mechanics, thermal and electrical of alloy materials with different kinds and different specification have been got. The performance and its character of alloy materials have been grasped in the state of analog ground fault by analysis and processing. The research results...

  11. Irreversible entropy model for damage diagnosis in resistors

    Science.gov (United States)

    Cuadras, Angel; Crisóstomo, Javier; Ovejas, Victoria J.; Quilez, Marcos

    2015-10-01

    We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4-8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.

  12. Noise characteristics of resistors buried in low-temperature co-fired ceramics

    CERN Document Server

    Kolek, A; Dziedzic, A

    2003-01-01

    The comparison of noise properties of conventional thick film resistors prepared on alumina substrates and resistors embedded in low-temperature co-fired ceramics (LTCCs) is presented. Both types of resistors were prepared from commercially available resistive inks. Noise measurements of LTCC resistors below 1 kHz show Gaussian 1/f noise. This is concluded from the calculations of the second spectra as well as from studying the volume dependence of noise intensity. It has occurred that noise index of LTCC resistors on average is not worse than that of conventional resistors. A detailed study of co-fired surface resistors and co-fired buried resistors show that burying a resistor within LTCC substrate usually leads to (significant) enhancement of resistance but not of noise intensity. We interpret this behaviour as another argument in favour of tunnelling as the dominant conduction mechanism in LTCC resistors.

  13. Divide and Conquer

    OpenAIRE

    Posner, Eric A.; Spier, Kathryn E.; Vermeule, Cornelius Adrian

    2010-01-01

    The maxim “divide and conquer” (divide et impera) is invoked frequently in law, history, and politics, but often in a loose or undertheorized way. We suggest that the maxim is a placeholder for a complex of ideas related by a family resemblance, but differing in their details, mechanisms and implications. We provide an analytic taxonomy of divide and conquer mechanisms in the settings of a Stag Hunt Game and an indefinitely-repeated Prisoners' Dilemma. A number of applications are considered,...

  14. Experimental study of Evanohm thin film resistors at subkelvin temperatures

    International Nuclear Information System (INIS)

    Thin film resistors, based on the Evanohm (Ni75%Cr20%Cu2.5%Al2.5%) alloy, have been investigated at cryogenic temperatures. The objective of the study is the development of the high value resistor for precision electrical measurements at low temperature and particularly for metrological triangle experiments. Thin film resistors of different configurations have been designed and fabricated by the thermal evaporation process. The resistivity of investigated resistors is 110 × 10?8 ? m; the resistance exhibits a Kondo minimum at a temperature near 30 K and increases with further reduction of temperature. In the temperature range 50–65 mK, the temperature coefficient reaches ?20 × 10?3 K?1. Power dependence measurements at subkelvin temperatures demonstrate that noticeable electron overheating takes place only at the power level above 10 pW for a 500 k? resistor. The electron–phonon coupling constant for the fabricated Evanohm thin films has been derived from experimental results

  15. Electrochemical Migration on Electronic Chip Resistors in Chloride Environments

    DEFF Research Database (Denmark)

    Minzari, Daniel; Jellesen, Morten Stendahl

    2009-01-01

    Electrochemical migration behavior of end terminals on ceramic chip resistors (CCRs) was studied using a novel experimental setup in varying sodium chloride concentrations from 0 to 1000 ppm. The chip resistor used for the investigation was 10-k? CCR size 0805 with end terminals made of 97Sn3Pb alloy. Anodic polarization behavior of the electrode materials was investigated using a microelectrochemical setup. Material makeup of the chip resistor was investigated using scanning electron microscopy (SEM)/energy dispersive spectroscopy and focused-ion-beam SEM. Results showed that the dissolution rate of the Sn and stability of Sn ions in the solution layer play a significant role in the formation of dendrites, which is controlled by chloride concentration and potential bias. Morphology, composition, and resistance of the dendrites were dependent on chloride concentration and potential.

  16. Ti-Cr-Al-O Thin Film Resistors

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, A F; Hayes, J P

    2002-03-21

    Thin films of Ti-Cr-Al-O are produced for use as an electrical resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O{sub 2}. Vertical resistivity values from 10{sup 4} to 10{sup 10} Ohm-cm are measured for Ti-Cr-Al-O films. The film resistivity can be design selected through control of the target composition and the deposition parameters. The Ti-Cr-Al-O thin film resistor is found to be thermally stable unlike other metal-oxide films.

  17. The Open Access Divide

    Directory of Open Access Journals (Sweden)

    Jingfeng Xia

    2013-10-01

    Full Text Available This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do not. It provides a structured description by adopting the Ws doctrines emphasizing such questions as who, what, when, where and why for information-gathering. Using measurable variables to define a common expression of the open access divide, this study collects aggregated data from existing open access as well as non-open access publications including journal articles and extensive reports. The definition of the open access divide is integrated into the discussion of scholarship on a larger scale.

  18. Air-cooled fast discharge resistors for ITER magnets

    International Nuclear Information System (INIS)

    The ITER superconducting magnets will store up to 50 GJ of magnetic energy per operation cycle. In case of coil quench the energy stored in the coils must be extracted rapidly with a time constant from 7.5 to 14 s. It will be achieved by fast discharge resistors (FDR) normally bridged by circuit breakers and inserted in series with the superconducting coils. The fast discharge of the coils results practically in adiabatic heating of the resistive elements up to 200-300 deg. C. The resistors need to be cooled to the initial temperature over 6-8 h. Natural air circulation is proposed as a cooling method. In order to simulate the temperature response of the resistors to energy released in the resistive plates and to demonstrate their cooling capability within the required time by natural air circulation the numerical model of the resistor cooling circuit has been developed. As the calculations have shown, the developed FDR cooling system based on cooling by natural air circulation is capable of providing the required temperature operation regime of FDRs, but the supply channels are to be optimized so that the cooling time does not exceed the permissible one.

  19. Hierarchy of Critical Exponents on Sierpinski fractal resistor networks

    OpenAIRE

    Jafarizadeh, M. A.; Mirzaee, M.; Aghlara, H.

    2000-01-01

    Using the S_3-symmetry of Sierpinski fractal resistor networks we determine the current distribution as well as the multifractals spectrum of moments of current distribution by using the real space renormalization group technique based on ([q/4]+1) independent Schure's invariant polynomials of inwards flowing currents.

  20. Bridging the urological divide

    OpenAIRE

    Roberts Robin

    2011-01-01

    Abstract The advanced disease clinical presentations, higher morbidity and mortality rates and lack of available treatment options in prostate cancer care, attest to disparities in the delivery and outcomes of urological services in Black men of African lineage in both the Developed and Developing countries. This gap in health care and services in the global management of prostate cancer denotes the urological divide. Through the experience of a Developing country urologist with a comparative...

  1. Divided-Pulse Lasers

    OpenAIRE

    Lamb, Erin S.; Wright, Logan G.; Wise, Frank W.

    2014-01-01

    We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16-times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single mode fiber. Potential extensions of this concept are discussed.

  2. Investigation of OSL signal of resistors from mobile phones for accidental dosimetry

    CERN Document Server

    Mrozik, Anna; Bilski, Pawel; Gieszczyk, Wojciech

    2014-01-01

    Resistors from mobile phones, usually located near the human body, are considered as individual dosimeters of ionizing radiation in emergency situations. The resistors contain Al2O3, which is optically stimulated luminescence (OSL) material sensitive to ionizing radiation. This work is focused on determination of dose homogeneity within a mobile phones which was carried out by OSL measurements of resistors placed in different parts inside the mobile phone. Separate, commercially available resistors, similar in the shape and size to the resistors from circuit board of the studied mobile phone, were situated in different locations inside it. The irradiations were performed in uniform 60Co and 137Cs radiation fields, with the mobile phones connected and not connected to the cellular network. The dose decrease of 9% was measured for original resistors situated between layer of copper-clad laminate and battery, in comparison to the dose at the front of the phone. The resistors showed the lower signal when the mobi...

  3. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices.

    Science.gov (United States)

    Lotkhov, Sergey V

    2013-06-14

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ~ 20 mK for films with sheet resistivities as high as ~7 k?, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current. PMID:23670293

  4. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices

    International Nuclear Information System (INIS)

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage–current characteristics were measured at temperatures down to T ? 20 mK for films with sheet resistivities as high as ?7 k?, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current. (paper)

  5. The electromagnetic "memory" of a dc-conducting resistor

    CERN Document Server

    Gluskin, Emanuel

    2010-01-01

    A circuit-field problem is considered. A resistor conducting a constant current is argued to be associated with electromagnetic energy accumulated in the surrounded space, though contrary to the case of an inductor or a capacitor, this energy is always associated with both magnetic and electrical fields, not with a single respective classical state-variable, -- either current or voltage. The circuit-theory point of view that a resistor has no electromagnetic memory is accepted, but the necessarily involved (in view of the field argument) capacitance and inductiveness are argued then also not be associated with any memory. The mutually completing circuit and physical arguments are presented in the form of dialog between a physicist and an electrical engineer. A teacher can find the work be pedagogically useful.

  6. Circular Planar Resistor Networks with Nonlinear and Signed Conductors

    CERN Document Server

    Johnson, Will

    2012-01-01

    We consider the inverse boundary value problem in the case of discrete electrical networks containing nonlinear (non-ohmic) resistors. Generalizing work of Curtis, Ingerman, Morrow, Colin de Verdiere, Gitler, and Vertigan, we characterize the circular planar graphs for which the inverse boundary value problem has a solution in this generalized non-linear setting. The answer is the same as in the linear setting. Our method of proof never requires that the resistors behave in a continuous or monotone fashion; this allows us to recover signed conductances in many cases. We apply this to the problem of recovery in graphs that are not circular planar. We also use our results to make a frivolous knot-theoretic statement, and to slightly generalize a fact proved by Lam and Pylyavskyy about factorization schemes in their electrical linear group.

  7. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices

    Science.gov (United States)

    Lotkhov, Sergey V.

    2013-06-01

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ˜ 20 mK for films with sheet resistivities as high as ˜7 k?, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.

  8. Embedded Resistors and Capacitors in Organic and Inorganic Substrates

    Science.gov (United States)

    Gerke, Robert David; Ator, Danielle

    2006-01-01

    Embedded resistors and capacitors were purchased from two technology; organic PWB and inorganic low temperature co-fire ceramic (LTCC). Small groups of each substrate were exposed to four environmental tests and several characterization tests to evaluate their performance and reliability. Even though all passive components maintained electrical performance throughout environmental testing, differences between the two technologies were observed. Environmental testing was taken beyond manufacturers' reported testing, but general not taken to failure. When possible, data was quantitatively compared to manufacturer's data.

  9. Spin dependent trapping in a polycrystalline silicon integrated circuit resistor

    International Nuclear Information System (INIS)

    Spin dependent trapping of majority carriers at trivalent silicon centers in the grain boundaries of a polycrystalline silicon integrated circuit resistor has been observed. The phenomenon has been studied both in a silicon bicrystal and in thin-film polycrystalline silicon with essentially identical results. This not only identifies the trapping center responsible for the large barriers observed at silicon grain boundaries, but also demonstrates that the technique has the sensitivity required to work with actual microelectronic devices

  10. TaN resistor process development and integration.

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Kathleen (LMATA, Albuquerque, NM); Martinez, Marino John; Clevenger, Jascinda; Austin, Franklin H., IV (, LMATA, Albuquerque, NM); Sullivan, Charles Thomas; Wolfley, Steven L.; Patrizi, Gary A.; Vigil, Pablita S. (LMATA, Albuquerque, NM); Grine, Alejandro J.

    2010-05-01

    This paper describes the development and implementation of an integrated resistor process based on reactively sputtered tantalum nitride. Image reversal lithography was shown to be a superior method for liftoff patterning of these films. The results of a response surface DOE for the sputter deposition of the films are discussed. Several approaches to stabilization baking were examined and the advantages of the hot plate method are shown. In support of a new capability to produce special-purpose HBT-based Small-Scale Integrated Circuits (SSICs), we developed our existing TaN resistor process, designed for research prototyping, into one with greater maturity and robustness. Included in this work was the migration of our TaN deposition process from a research-oriented tool to a tool more suitable for production. Also included was implementation and optimization of a liftoff process for the sputtered TaN to avoid the complicating effects of subtractive etching over potentially sensitive surfaces. Finally, the method and conditions for stabilization baking of the resistors was experimentally determined to complete the full implementation of the resistor module. Much of the work to be described involves the migration between sputter deposition tools - from a Kurt J. Lesker CMS-18 to a Denton Discovery 550. Though they use nominally the same deposition technique (reactive sputtering of Ta with N{sup +} in a RF-excited Ar plasma), they differ substantially in their design and produce clearly different results in terms of resistivity, conformity of the film and the difference between as-deposited and stabilized films. We will describe the design of and results from the design of experiments (DOE)-based method of process optimization on the new tool and compare this to what had been used on the old tool.

  11. Voltage controlled resistor using quasi-floating-gate MOSFETs

    OpenAIRE

    Susheel Sharma

    2013-01-01

    A voltage controlled resistor (VCR) using quasi-floating-gate MOSFETs (QFGMOS) suitable for low voltage applications is presented. The performance of the VCR implemented with QFGMOS is compared with its floating-gate MOSFET (FGMOS) version. It was found that QFGMOS offers better performance than FGMOS in terms of frequency response, offsets and chip area. The VCR using QFGMOS offers high bandwidth and low power dissipation and yields high value of resistance as compared to its FGMOS counterpa...

  12. Tuneable PTC effect in polymer-wax-carbon composite resistors

    OpenAIRE

    Maeder, Thomas; Jacq, Caroline; Ammon, Ludivine; Ryser, Peter

    2013-01-01

    The resistivity dependence on temperature of composite resistors made of carbon fillers dispersed in an organic matrix are known to be strongly affected by the matrix thermal expansion. High positive temperature coefficient (PTC) effects, i.e. essentially switching from resistive to quasi-insulating behaviour, can be caused by phase changes in the matrix and the assorted volume expansion, a behaviour that has been previously shown with both simple organic waxes (low temperatures) and semicrys...

  13. Monitoring the digital divide

    International Nuclear Information System (INIS)

    It is increasingly important to support the large numbers of scientists working in remote areas and having low-bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste - a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent 'Recommendations of Trieste' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work. (author)

  14. Monitoring the Digital Divide

    International Nuclear Information System (INIS)

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work

  15. Investigation of OSL signal of resistors from mobile phones for accidental dosimetry

    International Nuclear Information System (INIS)

    Resistors from mobile phones, usually located near the human body, are considered as individual dosimeters of ionizing radiation in emergency situations. The resistors contain Al2O3, which is optically stimulated luminescence (OSL) material sensitive to ionizing radiation. This work is focused on determination of dose homogeneity within mobile phones which was carried out by OSL measurements of resistors placed in different parts inside the mobile phone. Separate, commercially available resistors, similar in the shape and size to the resistors from circuit board of the studied mobile phone, were situated in different locations inside it. The irradiations were performed in uniform 60Co and 137Cs radiation fields, with the mobile phones connected and not connected to the cellular network. The dose decrease of 9% was measured for original resistors situated between circuit board and battery, in comparison to the dose at the front of the phone. The resistors showed the lower signal when the mobile phone was connected to the cellular network, due to higher temperature inside the housing. The profile of fading was investigated within 3 month period for resistors irradiated with 1 Gy of gamma rays to estimate of the fading coefficient. - Highlights: • Impact of a mobile phone mode (switched on/off) on absorbed dose by resistors was showed. • The influence of the temperature during irradiation on absorbed dose was measured. • Dose distribution inside of a mobile phone was performed. • Fading factor of resistors was calculated

  16. Towards a Broader Understanding of the Participation Divide(s)

    OpenAIRE

    Christoph Lutz; Christian Pieter Hoffmann

    2014-01-01

    Online participation is a thriving topic in communication and Internet research. One prominent area within research on online participation focuses on participation divides. Participation divides are frequently understood as social inequalities in online content creation. To create a broader understanding of participation domains, and thereby participation divides, we conduct a systematic literature review. Analyzing 192 journal articles and conference proceedings, we identify central definit...

  17. Electrical Switching of Perovskite Thin-Film Resistors

    Science.gov (United States)

    Liu, Shangqing; Wu, Juan; Ignatiev, Alex

    2010-01-01

    Electronic devices that exploit electrical switching of physical properties of thin films of perovskite materials (especially colossal magnetoresistive materials) have been invented. Unlike some related prior devices, these devices function at room temperature and do not depend on externally applied magnetic fields. Devices of this type can be designed to function as sensors (exhibiting varying electrical resistance in response to varying temperature, magnetic field, electric field, and/or mechanical pressure) and as elements of electronic memories. The underlying principle is that the application of one or more short electrical pulse(s) can induce a reversible, irreversible, or partly reversible change in the electrical, thermal, mechanical, and magnetic properties of a thin perovskite film. The energy in the pulse must be large enough to induce the desired change but not so large as to destroy the film. Depending on the requirements of a specific application, the pulse(s) can have any of a large variety of waveforms (e.g., square, triangular, or sine) and be of positive, negative, or alternating polarity. In some applications, it could be necessary to use multiple pulses to induce successive incremental physical changes. In one class of applications, electrical pulses of suitable shapes, sizes, and polarities are applied to vary the detection sensitivities of sensors. Another class of applications arises in electronic circuits in which certain resistance values are required to be variable: Incorporating the affected resistors into devices of the present type makes it possible to control their resistances electrically over wide ranges, and the lifetimes of electrically variable resistors exceed those of conventional mechanically variable resistors. Another and potentially the most important class of applications is that of resistance-based nonvolatile-memory devices, such as a resistance random access memory (RRAM) described in the immediately following article, Electrically Variable Resistive Memory Devices (MFS-32511-1).

  18. Investigation of OSL signal of resistors from mobile phones for accidental dosimetry

    OpenAIRE

    Mrozik, Anna; Marczewska, Barbara; Bilski, Pawel; Gieszczyk, Wojciech

    2014-01-01

    Resistors from mobile phones, usually located near the human body, are considered as individual dosimeters of ionizing radiation in emergency situations. The resistors contain Al2O3, which is optically stimulated luminescence (OSL) material sensitive to ionizing radiation. This work is focused on determination of dose homogeneity within a mobile phones which was carried out by OSL measurements of resistors placed in different parts inside the mobile phone. Separate, commerci...

  19. Universality and superuniversality of multifractals in nonlinear resistor networks

    International Nuclear Information System (INIS)

    The multifractal function f(?) is generalized to describe noisy nonlinear random resistor networks. An approximant function for the family of noise exponents is introduced that provides a good description of real percolative systems for strong nonlinearities. By mapping from this family to the multifractal function, one can approximate the latter. A scale transformation of ? in the approximation makes the multifractal function universal for all nonlinearities and by applying an additional transformation, this function becomes superuniversal, i.e., independent of the dimension. The universality is demonstrated for the Mandelbrot-Given structure and the implications of these results are discussed on real percolative systems

  20. Flory theory for conductivity of random resistor networks

    OpenAIRE

    Family, F.; Coniglio, A.

    1985-01-01

    We develop a Flory theory for the problem of conductivity in a d-dimensional random resistor network. We find that the conductivity exponent t is related to the fractal dimensionality df according to the Alexander-Orbach conjecture t = d - 2 + df/2, where consistently with Flory theory df = (d + 2)/2 for percolation and df = 2(d + 2)/5 for lattice animals. The results are in excellent agreement with the numerical estimates of t for percolation and in fair agreement for lattice animals.

  1. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices

    OpenAIRE

    Lotkhov, Sergey V.

    2013-01-01

    In this paper, we report on the fabrication and the low-temperature characterization of extremely high-ohmic microstrip resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to $T \\sim \\unit[20]{mK}$ for films with sheet resistivity up to as high as $\\sim \\unit[7]{k\\Omega}$, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates tha...

  2. Set, Reset, and Retention Times for Ionic and Filamentary Mem-Resistors

    OpenAIRE

    Mouttet, Blaise

    2011-01-01

    A dynamic systems model has previously been proposed for mem-resistors based on a driven damped harmonic oscillator differential equation describing electron and ionic depletion widths in a thin semiconductor film. This paper derives equations for set, reset, and retention times based on the previously proposed model. Keywords- mem-resistor, RRAM, ReRAM

  3. Effective thermal conductivity of real two-phase systems using resistor model with ellipsoidal inclusions

    Indian Academy of Sciences (India)

    Jagjiwanram; Ramvir Singh

    2004-08-01

    A theoretical model has been developed for real two-phase system assuming linear flow of heat flux lines having ellipsoidal particles arranged in a three-dimensional cubic array. The arrangement has been divided into unit cells, each of which contains an ellipsoid. The resistor model has been applied to determine the effective thermal conductivity (ETC) of the unit cell. To take account of random packing of the phases, non-uniform shape of the particles and non-linear flow of heat flux lines in real systems, incorporating an empirical correction factor in place of physical porosity modifies an expression for ETC. An effort is made to correlate it in terms of the ratio of thermal conductivities of the constituents and the physical porosity. Theoretical expression so obtained has been tested on a large number of samples cited in the literature and found that the values predicted are quite close to the experimental results. Comparison of our model with different models cited in the literature has also been made.

  4. Does the "digital divide" exist ?

    OpenAIRE

    Guichard, Eric

    2003-01-01

    This text begins with a criticism of discourses about the notion of ‘digital divide'. Regardless of the identity of their authors (politicians, G8 ‘experts', activists), these speeches are mostly based on technical determinism and on a confusion between information and its support. This paper studies the quality and the functions of the measures of the supposed ‘digital divide', that serve above all to legitimize a posteriori this notion of divide, whilst expressing prejudices about nations a...

  5. Stationary Regime of Random Resistor Networks Under Biased Percolation

    CERN Document Server

    Pennetta, C; Alfinito, E; Trefan, G

    2002-01-01

    The state of a 2-D random resistor network, resulting from the simultaneous evolutions of two competing biased percolations, is studied in a wide range of bias values. Monte Carlo simulations show that when the external current $I$ is below the threshold value for electrical breakdown, the network reaches a steady state with a nonlinear current-voltage characteristic. The properties of this nonlinear regime are investigated as a function of different model parameters. A scaling relation is found between $/_0$ and $I/I_0$, where $$ is the average resistance, $_0$ the linear regime resistance and $I_0$ the threshold value for the onset of nonlinearity. The scaling exponent is found to be independent of the model parameters. A similar scaling behavior is also found for the relative variance of resistance fluctuations. These results compare well with resistance measurements in composite materials performed in the Joule regime up to breakdown.

  6. Applications of the superconducting lossless resistor in electric power systems

    Science.gov (United States)

    Qian, Ping; Chen, Ji-yan; Hua, Rong; Chen, Zhongming

    2003-04-01

    The main features and some very useful applications of the superconducting lossless resistor (LLR) in electric power systems are introduced in this paper. According our opinion, there are two different kinds of LLR, i.e., the time-variant LLR (Tv-LLR) and the time-invariant LLR (Ti-LLR). First, Tv-LLR is well suited for developing new type of the fault-current limiter (FCL) since it has no heat energy dissipated from its superconducting element during current-limiting process. Second, it may be used to produce the high voltage circuit breaker with current limiting ability. While Ti-LLR may be used to manufacture a new type of the superconducting transformer, with compact volume, lightweight and with continuously regulated turn-ratio (so it familiarized as time-variable transformer, TVT).

  7. "Weak quantum chaos" and its resistor network modeling.

    Science.gov (United States)

    Stotland, Alexander; Pecora, Louis M; Cohen, Doron

    2011-06-01

    Weakly chaotic or weakly interacting systems have a wide regime where the common random matrix theory modeling does not apply. As an example we consider cold atoms in a nearly integrable optical billiard with a displaceable wall (piston). The motion is completely chaotic but with a small Lyapunov exponent. The Hamiltonian matrix does not look like one taken from a Gaussian ensemble, but rather it is very sparse and textured. This can be characterized by parameters s and g which reflect the percentage of large elements and their connectivity, respectively. For g we use a resistor network calculation that has a direct relation to the semilinear response characteristics of the system, hence leading to a prediction regarding the energy absorption rate of cold atoms in optical billiards with vibrating walls. PMID:21797470

  8. A novel charge sensitive preamplifier without the feedback resistor

    International Nuclear Information System (INIS)

    A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the first JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the forward baised gate to source junction and the current coming from the detector. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using an input JFET with a transconductance to gate capacitance ratio of 4 mS/5.4 pF

  9. Indium Tin Oxide Resistor-Based Nitric Oxide Microsensors

    Science.gov (United States)

    Xu, Jennifer C.; Hunter, Gary W.; Gonzalez, Jose M., III; Liu, Chung-Chiun

    2012-01-01

    A sensitive resistor-based NO microsensor, with a wide detection range and a low detection limit, has been developed. Semiconductor microfabrication techniques were used to create a sensor that has a simple, robust structure with a sensing area of 1.10 0.99 mm. A Pt interdigitated structure was used for the electrodes to maximize the sensor signal output. N-type semiconductor indium tin oxide (ITO) thin film was sputter-deposited as a sensing material on the electrode surface, and between the electrode fingers. Alumina substrate (250 m in thickness) was sequentially used for sensor fabrication. The resulting sensor was tested by applying a voltage across the two electrodes and measuring the resulting current. The sensor was tested at different concentrations of NO-containing gas at a range of temperatures. Preliminary results showed that the sensor had a relatively high sensitivity to NO at 450 C and 1 V. NO concentrations from ppm to ppb ranges were detected with the low limit of near 159 ppb. Lower NO concentrations are being tested. Two sensing mechanisms were involved in the NO gas detection at ppm level: adsorption and oxidation reactions, whereas at ppb level of NO, only one sensing mechanism of adsorption was involved. The NO microsensor has the advantages of high sensitivity, small size, simple batch fabrication, high sensor yield, low cost, and low power consumption due to its microsize. The resistor-based thin-film sensor is meant for detection of low concentrations of NO gas, mainly in the ppb or lower range, and is being developed concurrently with other sensor technology for multispecies detection. This development demonstrates that ITO is a sensitive sensing material for NO detection. It also provides crucial information for future selection of nanostructured and nanosized NO sensing materials, which are expected to be more sensitive and to consume less power.

  10. Investigation about decoupling capacitors of PMT voltage divider effects on neutron-gamma discrimination

    International Nuclear Information System (INIS)

    Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven’t discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor’s value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore, the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors

  11. Investigation about decoupling capacitors of PMT voltage divider effects on neutron-gamma discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Divani, Nazila, E-mail: n-divani@birjand.ac.ir; Firoozabadi, Mohammad M. [Dep. Of Physics, Faculty of Science, University of Birjand, Birjand (Iran, Islamic Republic of); Bayat, Esmail [Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran (Iran, Islamic Republic of)

    2014-11-24

    Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven’t discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor’s value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore, the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors.

  12. Investigation about decoupling capacitors of PMT voltage divider effects on neutron-gamma discrimination

    Science.gov (United States)

    Divani, Nazila; Bayat, Esmail; Firoozabadi, Mohammad M.

    2014-11-01

    Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven't discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor's value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore, the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors.

  13. Recursion-transform method for computing resistance of the complex resistor network with three arbitrary boundaries

    Science.gov (United States)

    Tan, Zhi-Zhong

    2015-05-01

    We develop a general recursion-transform (R-T) method for a two-dimensional resistor network with a zero resistor boundary. As applications of the R-T method, we consider a significant example to illuminate the usefulness for calculating resistance of a rectangular m ×n resistor network with a null resistor and three arbitrary boundaries, a problem never solved before, since Green's function techniques and Laplacian matrix approaches are invalid in this case. Looking for the exact calculation of the resistance of a binary resistor network is important but difficult in the case of an arbitrary boundary since the boundary is like a wall or trap which affects the behavior of finite network. In this paper we obtain several general formulas of resistance between any two nodes in a nonregular m ×n resistor network in both finite and infinite cases. In particular, 12 special cases are given by reducing one of the general formulas to understand its applications and meanings, and an integral identity is found when we compare the equivalent resistance of two different structures of the same problem in a resistor network.

  14. New internal multi-range resistors for ac voltage calibration by using TVC

    Science.gov (United States)

    Ali, Rasha S. M.

    2015-10-01

    Accurate calibration of ac voltages up to 1000?V by using thermal converters requires range resistors connected in series with the converter. The combination of a thermal converter and range resistor is known as the thermal voltage converter. In this paper, multi-range internal range resistors are designed and implemented in the National Institute for Standards (NIS), Egypt to cover the ac voltage ranges from 10?V to 750?V. The range resistor values are 2 k?, 10 k?, 20 k?, 40 k?, 100 k?, and 150 k? to cover the voltage ranges 10?V, 50?V, 100?V, 200?V, 500?V, and 750?V, respectively. The six range resistors are mounted in series with a single-junction thermo-element in the same box to provide a new thermal voltage converter. The required range resistor is selected by using a six-pin selector switch. Each resistor is connected to a selector pin. The new thermal voltage converter ranges are automatically calibrated against other standard thermal voltage converters at different frequencies by using a LabVIEW program to determine their ac-dc transfer difference at each range. The expanded uncertainties are estimated according to the GUM for all ranges at different frequencies. The performance of the new thermal voltage converter is also evaluated by comparing its ac-dc differences and its accuracy in measuring the ac voltage at different frequencies with a traditional thermal voltage converter.

  15. Modeling of N-well device and N-well field resistors

    Science.gov (United States)

    Kumar Singh, Rahul; Roy, J. N.

    2006-11-01

    Modeling of both N-well device and N-well field is reported here. A simple model as well as an advanced model have been used to model both types of resistors. The modeling has been carried out using MATLAB 6.5 and equations derived from device physics. Detailed modeling of an N-well field resistor, which is not generally available in the literature, has been carried out in great details. The results of various models applicable to different types of N-well resistors have been compared with operating conditions kept the same. A simulation strategy for circuit design has also been suggested.

  16. Design and Implementation of Coupled-Line Wilkinson Power Dividers Using Alumina Substrate

    Directory of Open Access Journals (Sweden)

    Taufiqqurrachman

    2014-03-01

    Full Text Available This paper presents design and implementation of coupled-line Wilkinson power dividers at frequency 2.4GHz using alumina substrate. This design using Wilkinson power dividers method where consist of two ??? impedance in the form of coupled lines on microstrip and one resistor is connected on the both of output ports. Design parameters used in the design of coupled lines dividers are input and output matching, insertion loss and isolation between the both output ports. The design parameters presented in graph on the simulation result from ADS2011.10 software simulation and the measurement result from vector network analyzer (VNA R3770 from Advantest. The simulation and measurement results show almost the same results where the return loss is less than -15dB, insertion loss is about -3dB and isolation between the output ports is more than -12dB.

  17. Ion backscattering study of tantalum nitride thin film resistors

    International Nuclear Information System (INIS)

    Ion backscattering was used to characterize thin film tantalum nitride resistors with thicknesses in the range 500--600 A. The amount of surface oxide, the nitrogen content, its depth distribution, the amount of argon-sputtering gas incorporated into the film, and its depth distribution, are measured directly by the technique. The films were prepared by diode sputtering in a pilot line facility. All sputtering parameters were held constant except for the N2 flowrate, which was varied so as to change the nitrogen concentration in the films. The electrical properties of the films were characterized by measurements of the sheet resistance and the differential Seebeck voltage. Aluminum oxide substrates were used for the electrical measurements and beryllium substrates with thin oxide layers were used for the backscattering compositional analysis. As the N concentration decreased below the stoichiometric composition Ta2N to the composition Ta2N0.5, the resistivity was found to decrease linearly by 25 percent and the differential Seebeck voltage to increase linearly by 90 percent. (U.S.)

  18. Cortical responses to sustained and divided attention in Alzheimer's disease

    DEFF Research Database (Denmark)

    Johannsen, Peter; Jakobsen, Johannes Klitgaard; Bruhn, Peter; Gjedde, A

    1999-01-01

    Neuropsychological data suggests that divided attention is more impaired than sustained attention during the early phases of Alzheimer's disease. The purpose of the present study was to compare cerebral activation patterns during sustained and divided attention between Alzheimer patients and healthy elderly. The O-15-water PET activation method was used to map sustained and divided attention in 16 patients with Alzheimer's disease (mean age +/- SD: 68 +/- 5 years; MMSE: 11-25, mean +/- SD = 19.5...

  19. Implementation of an analogue model of a memristor based on a light-dependent resistor

    International Nuclear Information System (INIS)

    In this paper, an analogue model of a memristor using a light-dependent resistor (LDR) is presented. This model can be simplified into two parts: a control circuit and a variable resistor. It can be used to easily verify theoretical presumptions about the switching properties of memristors. This LDR-based memristor model can also be used in both simulations and experiments for future research into memristor applications. The paper includes mathematical models, simulations, and experimental results

  20. An Investigation of the Relationship between Resistance and Thickness of Deposited Nickel Thin Film Resistors

    Directory of Open Access Journals (Sweden)

    Ericam R.R. Mucunguzi-Rugwebe

    2013-09-01

    Full Text Available The main purpose of this study is finding the relationship between resistance and thickness of deposited Nickel Thin Film Resistors. It was found that the Sheet Resistance, Rs, is inversely proportional to the thickness of the film on the substrate. It was also observed that when the film thickness is greater than 50 nm, films behave like ordinary resistors. In other words in bulk, films obey Ohm’s law if other physical quantities remain constant.

  1. Sensitivity enhancement of polysilicon piezo-resistive pressure sensors with phosphorous diffused resistors

    Energy Technology Data Exchange (ETDEWEB)

    Sivakumar, K [Microelectronics and MEMS Research Laboratory, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai -600 036 (India); Dasgupta, N [Microelectronics and MEMS Research Laboratory, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai -600 036 (India); Bhat, K N [Microelectronics and MEMS Research Laboratory, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai -600 036 (India); Natarajan, K [Small signal Devices, Bharat Electronics, Bangalore-560 013 (India)

    2006-04-01

    It is generally accepted that the piezo-resistive coefficient in single crystal silicon is higher when P-type impurities such as boron are used for doping the resistors. In this paper we demonstrate that the sensitivity of polycrystalline silicon piezo-resistive pressure sensors can be enhanced considerably when phosphorus diffusion source is used instead of boron dopant for realizing the piezo-resistors. Pressure sensors have been designed and fabricated with the polycrystalline piezo-resistors connected in the form of a Wheatstone bridge and laid out on thermal oxide grown on membranes obtained with a Silicon On Insulator (SOI) approach. The SOI wafers required for this purpose have been realized in-house by Silicon Fusion Bonding (SFB) and etch back technique in our laboratory. This approach provides excellent isolation between the resistors and enables zero temperature coefficient of the polysilicon resistor. The results obtained in our laboratory have clearly demonstrated that by optimizing the phosphorus diffusion temperature and duration, it is possible to achieve sensitivities in excess of 20mV /Bar for bridge input voltage of 10V, with linearity within 1% over a differential pressure range up to 10Bar (10 {sup 6}Pascal), and burst pressure in excess of 50 Bar as compared to the 10mV /Bar sensitivity obtained with boron doped polysilicon piezo-resistors. This enhancement is attributed to grain boundary passivation by phosphorous atoms.

  2. Aristotle on Dividing the Soul

    Directory of Open Access Journals (Sweden)

    Pavel Gregoric

    2008-11-01

    Full Text Available Aristotle’s account of the soul requires an adequate division of the soul. However, Aristotle refuses to divide the soul spatially, and insists that it is divided only conceptually, that is ‘in being’ or ‘in account’. In this paper I explain what this division amounts to and how Aristotle executes it. Then I discuss three important advantages of such a division of the soul. First, it enables Aristotle to avoid problems that he identified in Plato’s account of the soul. Second, it allows him to treat a particular capacity of the soul as itself divided into distinct parts or aspects. Third, it allows him to treat a particular capacity of the soul as a distinct part or aspect of some more comprehensive capacity.

  3. Noise properties of Pb/Cd-free thick film resistors

    International Nuclear Information System (INIS)

    Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO2- and CaRuO3-based thick films screen printed on alumina substrates. Experiments were performed in the temperature range 77-300 K and the frequency range 0.5-5000 Hz with multiterminal devices. The measured noise has been recognized as resistance noise that consists of background 1/f noise and components generated by several thermally activated noise sources (TANSs) of different activation energies. The total noise has been composed of the contributions generated in the resistive layer and in the resistive/conductive layers interface. These noise sources are non-uniformly distributed in the resistor volume. Noise intensity of new-resistive layers has been described by the noise parameter Cbulk. Pb/Cd-free layers turned out to be noisier than their Pb-containing counterparts; however, the removal of Pb and Cd from resistive composition is hardly responsible for the increase in the noise. In the case of RuO2 layers noise increases most likely due to larger grain size of RuO2 powder used to prepare resistive pastes. Information on the quality of the resistive-to-conductive layers interface occurred to be stored in the values of noise parameter Cint. Pb/Cd-free RuO2-based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO3-based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

  4. Information Societies and Digital Divides

    CERN Document Server

    Sorj, Bernardo

    2008-01-01

    The book argues ICT are part of the set of goods and services that determine quality of life, social inequality and the chances for economic development. Therefore understanding the digital divide demands a broader discussion of the place of ICT within each society and in the international system. The author argues against the perspectives that either isolates ICT from other basic social goods (in particular education and employment) as well as those that argue that new technologies are luxury of a consumer society. Though the author accepts that new technologies are not a panacea for the problems of inequality, access to them become a condition of full integration of social life. Using examples mainly from Latin America, the work presents some general policy proposals on the fight against the digital divide which take in consideration other dimensions of social inequality and access to public goods. Bernardo Sorj was born in Montevideo, Uruguay. He is a naturalized Brazilian, living in Brazil since 1976. He ...

  5. Information Societies and Digital Divides

    OpenAIRE

    Sorj, Bernardo (Coord.)

    2008-01-01

    The book argues ICT are part of the set of goods and services that determine quality of life, social inequality and the chances for economic development. Therefore understanding the digital divide demands a broader discussion of the place of ICT within each society and in the international system. The author argues against the perspectives that either isolates ICT from other basic social goods (in particular education and employment) as well as those that argue that new tech...

  6. Thermometric characteristics of some 1/8W carbon resistors in the millikelvin range

    International Nuclear Information System (INIS)

    Gotch and Awano (Cryogenic Engineering (Tokyo); 8:18 (1973)) have reported on the useful characteristics of 1/8W 100? Matsushita carbon resistors (grade ERC-18GK) as thermometers for the region 0.4K and 4.2K. Measurements on the resistance characteristics of this grade of resistors from 11mK to 1K are reported here. Nominal resistances of 56?, 68?, 82?, 100?, and 220? have been measured. It is found that the 56?, 68? and 82 ? resistors make useful thermometers down to at least 11mK. A comparison of the resistance behaviour of units immersed in dilute He3-He4 with those outside the liquid is also made. (author)

  7. Chemical interaction in resistors based on lead ruthenite with additions of niobium(5) oxide compounds

    International Nuclear Information System (INIS)

    The method of X-ray phase analysis was used to study chemical interaction in isothermal cross-section of Pb2RU2O6-Nb2O5, Rbsub(2)Rusub(2)Osub(6)-NbWOsub(5.5) and Rb2Ru2O6-Pb2Nb2O7 systems at 850 deg C as well as in models of real ruthenium resistors. Chemical interaction is stated to take place in systems with niobium (5) oxide and NbWOsub(5.5). Niobium (5) and tungsten (6) displace ruthenium (4) from its compounds with formation of their lead salts. Similar chemical interactions between current-carrying phase of the resistor and modifiers representing niobium-containing take place in models of components of the studied systems take place in models of resistors

  8. Effect of Annealing Process on the Properties of Ni(55%Cr(40%Si(5% Thin-Film Resistors

    Directory of Open Access Journals (Sweden)

    Huan-Yi Cheng

    2015-10-01

    Full Text Available Resistors in integrated circuits (ICs are implemented using diffused methods fabricated in the base and emitter regions of bipolar transistor or in source/drain regions of CMOS. Deposition of thin films on the wafer surface is another choice to fabricate the thin-film resistors in ICs’ applications. In this study, Ni(55%Cr(40%Si(5% (abbreviated as NiCrSi in wt % was used as the target and the sputtering method was used to deposit the thin-film resistors on Al2O3 substrates. NiCrSi thin-film resistors with different thicknesses of 30.8 nm~334.7 nm were obtained by controlling deposition time. After deposition, the thin-film resistors were annealed at 400 °C under different durations in N2 atmosphere using the rapid thermal annealing (RTA process. The sheet resistance of NiCrSi thin-film resistors was measured using the four-point-probe method from 25 °C to 125 °C, then the temperature coefficient of resistance could be obtained. We aim to show that resistivity of NiCrSi thin-film resistors decreased with increasing deposition time (thickness and the annealing process had apparent effect on the sheet resistance and temperature coefficient of resistance. We also aim to show that the annealed NiCrSi thin-film resistors had a low temperature coefficient of resistance (TCR between 0 ppm/°C and +50 ppm/°C.

  9. Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

    Science.gov (United States)

    Kamata, Masahiro; Abe, Mayumi

    2012-01-01

    A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

  10. Cosmic Ray Measurements by Scintillators with Metal Resistor Semiconductor Avalanche Photo Diodes

    Science.gov (United States)

    Blanco, Francesco; La Rocca, Paola; Riggi, Francesco; Akindinov, Alexandre; Mal'kevich, Dmitry

    2008-01-01

    An educational set-up for cosmic ray physics experiments is described. The detector is based on scintillator tiles with a readout through metal resistor semiconductor (MRS) avalanche photo diode (APD) arrays. Typical measurements of the cosmic angular distribution at sea level and a study of the East-West asymmetry obtained by such a device are…

  11. Ni-Cr thin film resistor fabrication for GaAs monolithic microwave integrated circuits

    International Nuclear Information System (INIS)

    Different Ni-Cr alloys were sputter-deposited on silicon nitride-coated GaAs substrates and covered with a spin-coated polyimide layer to develop thin film metal resistors for GaAs monolithic microwave integrated circuits (MMICs). The contact to the resistors was made through vias in the polyimide layer by sputter-deposited Ti/Au interconnect metal. The variation of contact resistance, sheet resistance (R S) and temperature coefficient of resistance (TCR) of the Ni-Cr resistors with fabrication process parameters such as polyimide curing thermal cycles and surface treatment given to the wafer prior to interconnect metal deposition has been studied. The Ni-Cr thin film resistors exhibited lower R S and higher TCR compared to the as-deposited Ni-Cr film that was not subjected to thermal cycles involved in the MMIC fabrication process. The change in resistivity and TCR values of Ni-Cr films during the MMIC fabrication process was found to be dependent on the Ni-Cr alloy composition

  12. Crossroads - Bridging the Digital Divide

    Directory of Open Access Journals (Sweden)

    David Cobb

    2005-03-01

    Full Text Available It’s so good to be in Cambridge, it feels almost like home. Let me start by stating that in the past year ITMB, a successful map publisher in British Columbia, Canada published more paper map titles than at any time in their history. Similarly, the U.S. Geological Survey (USGS recently announced that they have ceased producing paper from their aerial photography archive and will only produce digital copies. I believe that both of these facts speak to the future of maps and digital data. It means there will be paper maps well into the future and there will be an increasing array of digital data - some of it reformatted, as in the USGS case, and most of it will be born digital. When asked to speak about GIS and its role in libraries I often find myself in a conundrum - am I here to slay the dragon, or to pet the dragon. The role of technology in libraries is not one that has been embraced by everyone, and often the technology itself seems to have been force-fed upon us. The library profession is not one that has historically been a proponent of change and the very nature of GIS is change. In one sense, we have been given the choice of becoming paper museums or, at the very least, making GIS technology available in our collections. Today, I would like to review the many ways that GIS is, or will, affect our collections. I will divide the presentation into a general overview of GIS in libraries, how it affects our acquisitions or collection development policies, its effect on cataloging, on reference services, staffing, and our web services. Then I will shift the focus a little and discuss the current situation at the Harvard Map Collection, the future role of legacy collections, and a look to the future.

  13. Next generation KATRIN high precision voltage divider for voltages up to 65kV

    CERN Document Server

    Bauer, S; Hochschulz, F; Ortjohann, H -W; Rosendahl, S; Thümmler, T; Schmidt, M; Weinheimer, C

    2013-01-01

    The KATRIN (KArlsruhe TRItium Neutrino) experiment aims to determine the mass of the electron antineutrino with a sensitivity of 200meV by precisely measuring the electron spectrum of the tritium beta decay. This will be done by the use of a retarding spectrometer of the MAC-E-Filter type. To achieve the desired sensitivity the stability of the retarding potential of -18.6kV has to be monitored with a precision of 3ppm over at least two months. Since this is not feasible with commercial devices, two ppm-class high voltage dividers were developed, following the concept of the standard divider for DC voltages of up to 100kV of the Physikalisch-Technische Bundesanstalt (PTB). In order to reach such high accuracies different effects have to be considered. The two most important ones are the temperature dependence of resistance and leakage currents, caused by insulators or corona discharges. For the second divider improvements were made concerning the high-precision resistors and the thermal design of the divider....

  14. Non-Gaussian Fluctuations in Biased Resistor Networks: Size Effects versus Universal Behavior

    CERN Document Server

    Pennetta, C; Reggiani, L; Ruffo, S

    2005-01-01

    We study the distribution of the resistance fluctuations of biased resistor networks in nonequilibrium steady states. The stationary conditions arise from the competition between two stochastic and biased processes of breaking and recovery of the elementary resistors. The fluctuations of the network resistance are calculated by Monte Carlo simulations which are performed for different values of the applied current, for networks of different size and shape and by considering different levels of intrinsic disorder. The distribution of the resistance fluctuations generally exhibits relevant deviations from Gaussianity, in particular when the current approaches the threshold of electrical breakdown. For two-dimensional systems we have shown that this non-Gaussianity is in general related to finite size effects, thus it vanishes in the thermodynamic limit, with the remarkable exception of highly disordered networks. For these systems, close to the critical point of the conductor-insulator transition, non-Gaussiani...

  15. Hot-electron effect in PdAu thin-film resistors with attached cooling fins

    Energy Technology Data Exchange (ETDEWEB)

    Pleikies, J; Flokstra, J [Low Temperature Division, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Usenko, O; Frossati, G [Kamerlingh Onnes Laboratory of the Leiden University, PO Box 9504, 2300 RA Leiden (Netherlands); Stolz, R; Fritzsch, L, E-mail: j.pleikies@tnw.utwente.n [Institute of Photonic Technology, PO Box 100239, D-07702 Jena (Germany)

    2009-11-15

    The sensitivity of superconducting electronics operated in the sub-Kelvin temperature range is usually limited by the hot-electron effect. Here, an increased thermal resistance due to a weakened electron-phonon coupling leads to a higher temperature of the electrons in the thin-film shunt resistors of the Josephson junctions. Cooling fins can be attached to weaken this effect. We characterized different configurations of resistors in PdAu with or without attached cooling fins by dissipating power and determining the effective electron temperature. This was done by directly measuring the Johnson noise with a SQUID amplifier. The results are compared to theory and numerical calculations on the electronic heat transport. The latter turns out to be a useful tool for the optimization of the thermal design of superconducting electronics.

  16. Conductivity of a square-lattice bond-mixed resistor network

    International Nuclear Information System (INIS)

    Within a real-space renormalization-group framework based on self-dual clusters, the conductivity of a square-lattice quenched bond-random resistor network is calculated, the conductance on each bond being g1 or g2 with probabilities (1-p) and p respectively. The group recovers several already known exact results (including slopes), and is consequently believed to be numerically quite reliable for almost all values of p, and all ratios g1/g2 (in particular, g1=0 and g1=infinite with finite g2 respectively correspond to the insulator-resitor and superconductor-resistor mixtures). In addition to that, an heuristic analytic expression is proposed for the conductivity which is believed to be a quite satisfactory approximation everywhere not too close to the percolation point. (Author)

  17. Recursion-transform approach to compute the resistance of a resistor network with an arbitrary boundary

    International Nuclear Information System (INIS)

    We consider a profound problem of two-point resistance in the resistor network with a null resistor edge and an arbitrary boundary, which has not been solved before because the Green’s function technique and the Laplacian matrix approach are invalid in this case. Looking for the exact solutions of resistance is important but difficult in the case of the arbitrary boundary since the boundary is a wall or trap which affects the behavior of a finite network. In this paper, we give a general resistance formula that is composed of a single summation by using the recursion-transform method. Meanwhile, several interesting results are derived by the general formula. Further, the current distribution is given explicitly as a byproduct of the method. (paper)

  18. Recursion-transform approach to compute the resistance of a resistor network with an arbitrary boundary

    Science.gov (United States)

    Tan, Zhi-Zhong

    2015-02-01

    We consider a profound problem of two-point resistance in the resistor network with a null resistor edge and an arbitrary boundary, which has not been solved before because the Green’s function technique and the Laplacian matrix approach are invalid in this case. Looking for the exact solutions of resistance is important but difficult in the case of the arbitrary boundary since the boundary is a wall or trap which affects the behavior of a finite network. In this paper, we give a general resistance formula that is composed of a single summation by using the recursion-transform method. Meanwhile, several interesting results are derived by the general formula. Further, the current distribution is given explicitly as a byproduct of the method.

  19. Transport nonuniversality and critical behavior of the piezoresistive response in thick-film resistors

    OpenAIRE

    Vionnet-Menot, Sonia; Grimaldi, Claudio; Maeder, Thomas; Ryser, Peter; Strässler, Sigfrid

    2003-01-01

    Thick-film resistors (TFRs) consist of a percolating network of conducting oxide nanoparticlesdispersed in an insulating glassy matrix, whose resistive properties are dominated by quantumtunneling across insulating layers separating adjacent conducting grains. Tunneling processes are at the origin of the high sensitivity of the TFRs resistances to applied strains. We have measuredtransport and piezoresistive response for different RuO2-based TFRs as a function of metallic concentration x and...

  20. Electrochemical, morphological and microstructural characterization of carbon film resistor electrodes for application in electrochemical sensors

    OpenAIRE

    Gouveia-Caridade, Carla; Soares, David M.; Liess, Hans-Dieter; Christopher M. A. Brett

    2008-01-01

    The electrochemical and microstructural properties of carbon film electrodes made from carbon film electrical resistors of 1.5, 15, 140 [Omega] and 2.0 k[Omega] nominal resistance have been investigated before and after electrochemical pre-treatment at +0.9 V vs SCE, in order to assess the potential use of these carbon film electrodes as electrochemical sensors and as substrates for sensors and biosensors. The results obtained are compared with those at electrodes made from previously investi...

  1. Development of resistor-type dummy load for high-voltage test operation

    International Nuclear Information System (INIS)

    We developed the resistor-type dummy load as a substitute for the klystron used in the factory test of the modulator. The dummy load can be used with 350 kV applied voltage, and 460 W input power in insulation oil. Compared to the klystron, the output waveforms are nearly same. Therefore, the dummy load has been used for the evaluation of the electrical characteristic of the modulator. The resistance value depends on the applied voltage, and varies secularly. (author)

  2. A study on embedded resistor components fabricated by laser micro-cladding and rapid prototype

    International Nuclear Information System (INIS)

    With the rapid development of IC and packaging, electronic devices are required to be smaller, to have a high-density integration, to become multifunction and to be of lower cost and high-reliability. Thick-film technology is not able to meet the current developing demands because of its shortcomings, such as the limit of pattern resolution, the severe torsion and delay of high-speed signal transmission. The speed and quality of signal transmission will be improved if embedded resistor components are directly integrated in the multiplayer substrate of multi-chip or laminated module, and high-density integration and reliability are achieved because the short interconnection and the less soldering point. In this paper, a technique named laser micro-cladding and rapid prototype is used to directly fabricate embedded resistor units on the multiplayer ceramic substrate without using a mask and high-temperature sintering, and without trimming resistor, which will simplify processing and decrease cost as well as improving high-speed and reliable performance

  3. Maximum Bandwidth Enhancement of Current Mirror using Series-Resistor and Dynamic Body Bias Technique

    Directory of Open Access Journals (Sweden)

    V. Niranjan

    2014-09-01

    Full Text Available This paper introduces a new approach for enhancing the bandwidth of a low voltage CMOS current mirror. The proposed approach is based on utilizing body effect in a MOS transistor by connecting its gate and bulk terminals together for signal input. This results in boosting the effective transconductance of MOS transistor along with reduction of the threshold voltage. The proposed approach does not affect the DC gain of the current mirror. We demonstrate that the proposed approach features compatibility with widely used series-resistor technique for enhancing the current mirror bandwidth and both techniques have been employed simultaneously for maximum bandwidth enhancement. An important consequence of using both techniques simultaneously is the reduction of the series-resistor value for achieving the same bandwidth. This reduction in value is very attractive because a smaller resistor results in smaller chip area and less noise. PSpice simulation results using 180 nm CMOS technology from TSMC are included to prove the unique results. The proposed current mirror operates at 1Volt consuming only 102 µW and maximum bandwidth extension ratio of 1.85 has been obtained using the proposed approach. Simulation results are in good agreement with analytical predictions.

  4. Unipolar sequential circuits based on individual-carbon-nanotube transistors and thin-film carbon resistors.

    Science.gov (United States)

    Ryu, Hyeyeon; Kälblein, Daniel; Schmidt, Oliver G; Klauk, Hagen

    2011-09-27

    A fabrication process for the monolithic integration of field-effect transistors based on individual carbon nanotubes and load resistors based on vacuum-evaporated carbon films into fast unipolar logic circuits on glass substrates is reported for the first time. The individual-carbon-nanotube transistors operate with relatively small gate-source and drain-source voltages of 1 V and combine large transconductance (up to 6 ?S), large ON/OFF ratio (>10(4)), and short switching delay time constants (12 ns). The thin-film carbon load resistors provide linear current-voltage characteristics and resistances between 300 k? and 100 M?, depending on the layout of the resistors and the thickness of the vacuum-evaporated carbon films. Various combinational circuits (NAND, NOR, AND, OR gates) as well as a sequential circuit ( ?S ?R NAND latch) have been fabricated and characterized. Although these unipolar circuits cannot compete with optimized complementary circuits in terms of integration density and static power consumption, they offer the possibility of realizing air-stable, low-voltage integrated circuits with promising static and dynamic performance on unconventional substrates for large-area electronics applications, such as displays or sensors. PMID:21870841

  5. Development of high power RF divider

    International Nuclear Information System (INIS)

    High power multi antenna RF heating system has been developed. The RF power of 500 KW (f = 7 - 28 MHz) is divided into twelve lines by means of 3 db coupler and two six channel power dividers, and those are fed to the twelve ICRF antennas through impedance matching circuits. (author)

  6. Social Welfare Implications of the Digital Divide

    Science.gov (United States)

    Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

    2009-01-01

    The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

  7. Zero-point energy in the Johnson noise of resistors: Is it there?

    OpenAIRE

    Kish, Laszlo B.

    2015-01-01

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor: Is it indeed there or is it only an experimental artifact due to the uncertainty principle for phase-sensitive amplifiers? We show that, when the zero-point term is measured by the mean energy and force in a shunting capacitor and, if these measurements confirm its existence, two types of perpetual motion machines could be constructed. Therefore an exact quantum theory of the...

  8. Generalized Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system using arbitrary resistors

    Science.gov (United States)

    Vadai, Gergely; Mingesz, Robert; Gingl, Zoltan

    2015-09-01

    The Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system has been introduced as a simple, very low cost and efficient classical physical alternative to quantum key distribution systems. The ideal system uses only a few electronic components—identical resistor pairs, switches and interconnecting wires—in order to guarantee perfectly protected data transmission. We show that a generalized KLJN system can provide unconditional security even if it is used with significantly less limitations. The more universal conditions ease practical realizations considerably and support more robust protection against attacks. Our theoretical results are confirmed by numerical simulations.

  9. Compact chromium oxide thin film resistors for use in nanoscale quantum circuits

    OpenAIRE

    Nash, C. R.; Fenton, J. C.; Constantino, N. G. N.; Warburton, P. A

    2014-01-01

    We report on the electrical characterisation of a series of thin chromium oxide films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the chromium oxide films was varied from 28$\\Omega / \\square$ to 32.6k$\\Omega / \\square$. The variation in resistance with cooling to 4.2K in liquid helium was investigated; the sheet resistance at 4.2K var...

  10. Zero-point energy in the Johnson noise of resistors: Is it there?

    CERN Document Server

    Kish, Laszlo B

    2015-01-01

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor: Is it indeed there or is it only an experimental artifact due to the uncertainty principle for phase-sensitive amplifiers? We show that, when the zero-point term is measured by the mean energy and force in a shunting capacitor and, if these measurements confirm its existence, two types of perpetual motion machines could be constructed. Therefore an exact quantum theory of the Johnson noise must include also the measurement system used to evaluate the observed quantities. The results have implications also for phenomena in advanced nanotechnology.

  11. High-Voltage Sensitivity Studies of Model Thick-Film Resistors

    OpenAIRE

    Johner, Niklaus; Maeder, Thomas; Grimaldi, Claudio; Kambli, Adrian; Saglini, Igor; Jacq, Caroline; Ryser, Peter

    2006-01-01

    In this work we seek to better understand the mechanisms governing pulse voltage trimming in disordered conductor-insulator composites. Therefore, we investigate the effect of the composition of thick-film resistors (TFRs) on sensitivity to high voltage pulses. We investigate four series of RuO2-based TFRs: two different glass compositions and two different RuO2 grain sizes. For each combination of glass and grain size, different RuO2 concentrations are studied. It is thought that the g...

  12. Experimental verification of temperature coefficients of resistance for uniformly doped P-type resistors in SOI

    International Nuclear Information System (INIS)

    Many today's microsystems like strain-gauge-based piezoresistive pressure sensors contain doped resistors. If one wants to predict correctly the temperature impact on the performance of such devices, the accurate data about the temperature coefficients of resistance (TCR) are essential. Although such data may be calculated using one of the existing mobility models, our experiments showed that we can observe the huge mismatch between the calculated and measured values. Thus, in order to investigate the TCR values, a set of the test structures that contained doped P-type resistors was fabricated. As the TCR value also depends on the doping profile shape, we decided to use the very thin, 340 nm thick SOI wafers in order to fabricate the quasi-uniformly doped silicon layers ranging from 2 × 1017 at cm?3 to 1.6 × 1019 at cm?3. The results showed that the experimental data for the first-order TCR are quite far from the calculated ones especially over the doping range of 1018–1019 at cm?3 and quite close to the experimental ones obtained by Bullis about 50 years ago for bulk silicon. Moreover, for the first time, second-order coefficients that were not very consistent with the calculations were obtained.

  13. New metal resistor bolometer for measuring vacuum ultraviolet and soft x radiation

    International Nuclear Information System (INIS)

    A new metal resistor bolometer has been developed by applying thin-film technology. It is composed of three layers, a 4-?m-thick radiation absorber made of gold, a 7.5-?m-thick kapton dielectric, and a 0.1-?m-thick 5-k? gold resistor. This detector with the appropriate electronics shows a linear response to radiation power, including both neutral-particle emission and electromagnetic radiation from the soft x-ray part of the spectrum to the infrared. The bolometer has a very high operating reliability and sufficient suppression of ambient interference under extreme environmental conditions, such as high neutron and gamma radiation fluxes, high temperatures, mechanical vibrations, and strong electromagnetic fields. In plasma discharges in the ASDEX tokamak a radiation detection limit of 100 ?W/cm2 was obtained at a time resolution of 10 ms. The bolometers of an array can be calibrated in situ; the calibration data are reproducible and stable in time within +- 10%. Measurements in ASDEX which demonstrate the capability of the method are discussed

  14. Compact chromium oxide thin film resistors for use in nanoscale quantum circuits

    Science.gov (United States)

    Nash, C. R.; Fenton, J. C.; Constantino, N. G. N.; Warburton, P. A.

    2014-12-01

    We report on the electrical characterisation of a series of thin amorphous chromium oxide (CrOx) films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the CrOx films was varied from 28 ?/? to 32.6 k ?/? . The variation in resistance with cooling to 4.2 K in liquid helium was investigated; the sheet resistance at 4.2 K varied with composition from 65 ?/? to above 20 G ?/? . All of the films measured displayed linear current-voltage characteristics at all measured temperatures. For on-chip devices for quantum phase-slip measurements using niobium-silicon nanowires, interfaces between niobium-silicon and chromium oxide are required. We also characterised the contact resistance for one CrOx composition at an interface with niobium-silicon. We found that a gold intermediate layer is favourable: the specific contact resistivity of chromium-oxide-to-gold interfaces was 0.14 m?cm2, much lower than the value for direct CrOx to niobium-silicon contact. We conclude that these chromium oxide films are suitable for use in nanoscale circuits as high-value resistors, with resistivity tunable by oxygen content.

  15. Compact chromium oxide thin film resistors for use in nanoscale quantum circuits

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. R.; Fenton, J. C.; Constantino, N. G. N.; Warburton, P. A. [London Centre for Nanotechnology, UCL, 17–19 Gordon Street, London WC1H 0AH (United Kingdom)

    2014-12-14

    We report on the electrical characterisation of a series of thin amorphous chromium oxide (CrO{sub x}) films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the CrO{sub x} films was varied from 28 ?/? to 32.6?k?/?. The variation in resistance with cooling to 4.2?K in liquid helium was investigated; the sheet resistance at 4.2?K varied with composition from 65 ?/? to above 20?G?/?. All of the films measured displayed linear current–voltage characteristics at all measured temperatures. For on-chip devices for quantum phase-slip measurements using niobium–silicon nanowires, interfaces between niobium–silicon and chromium oxide are required. We also characterised the contact resistance for one CrO{sub x} composition at an interface with niobium–silicon. We found that a gold intermediate layer is favourable: the specific contact resistivity of chromium-oxide-to-gold interfaces was 0.14 m?cm{sup 2}, much lower than the value for direct CrO{sub x} to niobium–silicon contact. We conclude that these chromium oxide films are suitable for use in nanoscale circuits as high-value resistors, with resistivity tunable by oxygen content.

  16. Accurate SPICE Modeling of Poly-silicon Resistor in 40nm CMOS Technology Process for Analog Circuit Simulation

    Directory of Open Access Journals (Sweden)

    Sun Lijie

    2015-01-01

    Full Text Available In this paper, the SPICE model of poly resistor is accurately developed based on silicon data. To describe the non-linear R-V trend, the new correlation in temperature and voltage is found in non-silicide poly-silicon resistor. A scalable model is developed on the temperature-dependent characteristics (TDC and the temperature-dependent voltage characteristics (TDVC from the R-V data. Besides, the parasitic capacitance between poly and substrate are extracted from real silicon structure in replacing conventional simulation data. The capacitance data are tested through using on-wafer charge-induced-injection error-free charge-based capacitance measurement (CIEF-CBCM technique which is driven by non-overlapping clock generation circuit. All modeling test structures are designed and fabricated through using 40nm CMOS technology process. The new SPICE model of poly-silicon resistor is more accurate to silicon for analog circuit simulation.

  17. A real time status monitor for transistor bank driver power limit resistor in boost injection kicker power supply

    International Nuclear Information System (INIS)

    For years suffering of Booster Injection Kicker transistor bank driver regulator troubleshooting, a new real time monitor system has been developed. A simple and floating circuit has been designed and tested. This circuit monitor system can monitor the driver regulator power limit resistor status in real time and warn machine operator if the power limit resistor changes values. This paper will mainly introduce the power supply and the new designed monitoring system. This real time resistor monitor circuit shows a useful method to monitor some critical parts in the booster pulse power supply. After two years accelerator operation, it shows that this monitor works well. Previously, we spent a lot of time in booster machine trouble shooting. We will reinstall all 4 PCB into Euro Card Standard Chassis when the power supply system will be updated.

  18. Thermal analysis and temperature characteristics of a braking resistor for high-speed trains for changes in the braking current

    Science.gov (United States)

    Lee, Dae-Dong; Kang, Hyun-Il; Shim, Jae-Myung

    2015-09-01

    Electric brake systems are used in high-speed trains to brake trains by converting the kinetic energy of a railway vehicle to electric energy. The electric brake system consists of a regenerative braking system and a dynamic braking system. When the electric energy generated during the dynamic braking process is changed to heat through the braking resistor, the braking resistor can overheat; thus, failures can occur to the motor block. In this paper, a braking resistor for a high-speed train was used to perform thermal analyses and tests, and the results were analyzed. The analyzed data were used to estimate the dependence of the brake currents and the temperature rises on speed changes up to 300 km/h, at which a test could not be performed.

  19. Bruce B Unit 6 divider plate sealing skin installation

    International Nuclear Information System (INIS)

    Bruce Unit 6 went into service in 1984, since its initial startup reactor inlet header temperatures have risen steadily. In 1999 reactor inlet header (RIH) temperatures had risen to the point that extraction steam to both high pressure feed water heaters had being valved out of service in an effort to keep boiler pressures above the units safe operating margin and RIH temperatures low. It was projected if no action was taken to reduce RIH temperature levels unit derating would start in 2000 and continue at a rate of 0.8% reactor power per year (-5.7Megawatts). Experience gained from the Bruce A units and other CANDU stations with segmented divider plates pointed to two main contributors to RIH temperature increases, divider plate leakage and boiler tube ID fouling. Divider plate leakage is a measurable condition, with proven results if corrected. Boiler tube ID fouling on the other hand was a measurable condition via eddy current and oxi-probe inspections, however only limited data existed at that time as to its effect on RIHT. In addition the effectiveness of ID cleaning was unknown and the equipment and process needed conversion and qualification for Bruce units. The decision was made to reduce the divider plate leakage now, and later perform an ID clean if the process proves beneficial. For reasons of cost, time (design and installation), dose and remaining boiler life, Bruce B design engineering decided that sealing the divider plates best suited the stations needs. During the last few years of Bruce A's operation a design was developed that would seal the existing divider plates rather than replacement. The sealing design consisted of a thin stainless steel sealing skin that covered the entire segmented divider plate plus all peripheral seams. Thicker stainless steel clamping plates covered the sealing skin panels to hold them in place and provide erosion protection. The sealing skin and clamping plates were held in place by utilizing the bolt patterns of the original divider plate design. No welding was required. The installation process proceeded as planned, actual installation time was approx. 20 days including opening, decontamination, installation and closing of all 8 boilers. The cost was approx. $2M. Dose received during the installation was 20 man Rem. On return to full power station thermal performance staff reported a 3 to 4 deg C reduction in RIHT levels. Boiler pressures had risen from 4120kpa before the outage to 4400 kpa. Gross power production had increased by 20 Megawatts. (author)

  20. Conquering the digital divide: Botswana and South Korea digital divide status and interventions

    Directory of Open Access Journals (Sweden)

    Nonofo C. Sedimo

    2011-03-01

    Full Text Available Background: Botswana is putting in place initiatives towards establishing itself as a knowledgebased economy. Transformation from a resource-based to a knowledge-based economy is partly hinged on innovation, research and development capability, knowledge channels, and the funding of research and development activities.Objectives: Bridging the digital divide and narrowing the intra-national divide brings about global information and communication technology (ICT usage that translates into changing work patterns and eventually transformed economies. This article outlines the different interventions implemented in Botswana to bridge the divide. The South Korean experience in bridging the divide is discussed so as to serve as lessons on how to effectively bridge the divide to Botswana’s initiatives.Method: Using a mix of exploratory and empirical study, this article presents the findings on the status of ICT uptake in Botswana and investigates the level of the digital divide in the country.Results: The results of the study show that the digital divide is much more evident in Botswana than in South Korea. South Korea has put in place robust strategic initiatives towards reducing the digital divide and this has largely transcended into its transformation into a full-fledged knowledge society.Conclusion: This article is timely as it unearths the different pointers that may be utilised in policy formation and what interventions need to be taken at both the individual and national level to bridge the digital divide.

  1. Surface-modified RuO2-based thick film resistors using Nd:YAG laser

    Science.gov (United States)

    Gofuku, E.; Ogama, T.; Takasago, H.

    1989-12-01

    An RuO2-based thick film resistor (TFR) is a cermet-type resistor which consists of RuO2 particles and glass. Paste containing organic vehicles is printed onto an insulating substrate, and subsequent firing at about 900 °C makes the cermet-type resistors. TFRs are widely utilized as electrical resistive materials in electric devices such as hybrid ICs (integrated circuits) [see, for example, R. W. Vest, Ceram. Bull. 65, 631 (1986)]. The features of an advanced laser application process to control the electrical resistivity of the TFRs were proposed. This new process is an application of surface-modification using laser beams. In this paper, a mechanism of the surface-modification of the TFR is considered using results of morphology observation, x-ray diffraction (XRD), and x-ray photoemission spectroscopy (XPS). The following points should be noticed. (1) In the surface-modifying process using normal mode pulse Nd:YAG laser beams, glass in the TFR is modified and supersaturated with ruthenium impurities because of rapid heating and rapid cooling rates in the irradiation process; the specific resistivity of the modified glass is extremely decreased, estimated at 10-3 ? cm at most. (2) No new crystalline phase in the ruthenium-oxygen system is detected after the surface modification by results of x-ray diffraction (XRD) analysis. (3) The valence state of the ruthenium ions in the modified glass is more positively charged than that in crystalline RuO2 , while the valence states of lead and oxygen ions in the modified glass are more negatively charged than in as-fired glass before surface modification according to the results obtained by x-ray photoemission spectroscopy (XPS) analysis. It is suggested that if ruthenium ions introduce electrons into the modified glass and if these electrons behave as itinerant electron carriers in the modified glass, a decrease in the resistivity of TFR after the surface modification is quite reasonable for the results of XPS.

  2. Jitter and phase noise in frequency dividers.

    Czech Academy of Sciences Publication Activity Database

    Kroupa, V?nceslav František

    2001-01-01

    Ro?. 50, ?. 5 (2001), s. 1241-1243. ISSN 0018-9456 R&D Projects: GA ?R GA102/00/0958 Institutional research plan: CEZ:AV0Z2067918 Keywords : signal processing * frequency dividers * frequency synthesizers * phase locked loops Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.900, year: 2001

  3. Young People's Internet Use: Divided or Diversified?

    Science.gov (United States)

    Boonaert, Tom; Vettenburg, Nicole

    2011-01-01

    This article critically analyses research on young people's internet use. Based on a literature analysis, it examines which young people do what on the internet. These results invite a reflection on the dominant discourse on the digital divide. Within this discourse, there is a strong focus on the use of the internet for information purposes only,…

  4. Bridging the digital divide with mobile services

    CERN Document Server

    Yelton, Andromeda

    2013-01-01

    In this issue of Library Technology Reports, Andromeda Yelton shows how libraries can build on the breadth of this population to help bridge the digital divide and provide even greater access to information. Yelton breaks down the demographics of mobile internet users, provides examples of how different libraries are reaching out to these populations, and suggests what the future may hold for this trend.

  5. Programmable diode/resistor-like behavior of nanostructured vanadium pentoxide xerogel thin film.

    Science.gov (United States)

    Wan, Zhenni; Darling, Robert B; Anantram, M P

    2015-11-11

    Electrical properties of a Cr/V2O5/Cr structure are investigated and switching of the device due to electrochemical reactions is observed at low bias (film are involved in the electrochemical reactions. It is proposed that an interfacial layer with reduced oxidation state forms at the Cr/V2O5 interface, and creates a higher Schottky barrier due to rise of electron affinity. Different interfacial layer thicknesses in forward and reverse first sweeps are responsible for different I-V characteristics in subsequent sweeps. The results suggest future applications of these V2O5 thin films in low-power read-only memory devices and diode-resistor networks. PMID:26529244

  6. Developments in the use and design of a suspended resistor IR scene projector technology

    Science.gov (United States)

    Pritchard, Alan P.; Lake, Stephen P.; Sturland, Ian M.; Balmond, Mark D.; Gough, David W.; Venables, Mark A.

    1995-06-01

    This paper describes two aspects of work carried out at British Aerospace on a family of suspended resistor infrared scene generators intended as sources for exercising infrared seeker systems in simulation environments. In the first aspect, a 256 X 256 system has matured and entered service with hardware-in-the-loop (HWIL) simulation facilities. This system, designated TPS4 (for thermal picture synthesizer) has performance suitable for air target tracking studies, and certain aspects of its characteristics in use are described. In the second aspect, research work has been carried out on the extension of the system performance to enable the representation of higher temperature targets, such as are required for countermeasures work. These improved devices are designated TPS5, and aspects of their rationale, design, and evaluation are described. Prototype arrays suitable for eventual systems of complexity 512 X 512 and beyond have been tested.

  7. Resistor Type Superconducting Fault Current Limiter: Optimum Shunt Resistance Determination to Enhance Power System Transient Stability

    Science.gov (United States)

    Hooshyar, Hossein; Heydari, Hossein; Savaghebi, Mehdi; Sharifi, Reza

    In power systems, Resistor type Superconducting Fault Current Limiters (RSFCL) can limit the prospective short-circuit currents to lower levels, so that the underrated switchgears can operate safely. Besides, RSFCLs can enhance the power system transient stability if they are accompanied by appropriate shunt resistances. This paper presents a method of optimum shunt resistance determination for transient stability improvement. The method is based on minimization of rotor kinetic energy oscillations. Meanwhile to make it more comprehensible, the method is utilized to determine the shunt resistances of three RSFCLs installed in a 9-bus 3-generator sample network. All of the simulations have been carried out by EMTP/ATP. The paper begins by modeling an RSFCL. Then RSFCL critical current determination is discussed in a model system. Finally, a method of optimum shunt resistance determination for transient stability improvement is presented.

  8. Actividades de experimentación con materiales de bajo coste para la enseñanza de física: resistores y capacitores de grafito

    Directory of Open Access Journals (Sweden)

    Marcos Alfredo Salami

    2007-04-01

    Full Text Available This work presents an investigation carried out at the Pontifical Catholic University of Rio Grande do Sul from April 2002 to December 2003, involving the feasibility of using resistors and capacitors made of graphite laid upon paper, cardboard and plastic, in order to help the learning of electricity through experimentation. Its specific focus was the contents on resistibility, calculation of equivalent resistance of serial and parallel associations of resistors and capacitors, dependence of capacitance to the area, to the distance between the boards and the shape of the boards. The low cost technique resulting from this development allows students to playfully manipulate variables involved in the definition of electric resistance and capacitance, besides making it possible for them to crate and modify freely the associations of resistors andcapacitors, by just using a multimeter with a capacimeter function, paper and a 6B type pencil. It also has a great potential to stimulate the comprehension and learning process of such contents once it is pleasant, simple and low costly. It also promotes the engagement and free participation of all students. Graphite has already been used in the production of resistors to measure individual resistance and associations as described in the article by (Rocha Filho et al., 2004, and also in the production of capacitors to measure the capacitances in the activities mentioned in the master’s dissertation of (Salami, 2004.

  9. Design note of a 10,000 amp 2 MJoules dump resistor for the magnet test facility

    International Nuclear Information System (INIS)

    This report contains the design notes of a 2 MJoules 10,000A, 1000V, dump resistor, with taps from 25 mOhms to 300 mOhms maximum. The resistor is forced air-cooled and can handle continuously one 2 MJ dump every 5 minutes at all taps. The resistor is made from 304 stainless steel bars and is mounted in a 90 in.H x 24 in.W x 20 in.D steel enclosure, with easy access to taps. The upper resistance sections are made lighter to save material cost and weight. The total weight of the resistance element is 427 lbs. The resistor is used to absorb the stored energy from cryogenic magnets during tests at the magnet test facility. Interlocks are provided for remote tap readout, dc over current and over temperature. A build-in current sensor and timing relay switch forced air-cooling on for 5 minutes, after a dump. 12 figs., 3 tabs

  10. Technical-economic evaluation of the utilization of closing resistor in CEMIG extra-high voltage circuit breakers

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Angelica C.O.; Pinto, Roberto del Giudice R.; Teixeira, Jose Cleber; Fonseca, Rodrigo Assuncao; F. Junior, Sebastiao V. [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

    1994-12-31

    This paper presents the technical and economic studies performed by CEMIG, Companhia Energetica de Minas Gerais, Brazil, concerning the use of closing resistor in its extra-high voltage (EHV) breakers. The analysis emphasizes the advantages which could be achieved with the elimination of the resistor as far as costs and reliability are concerned. This evaluation was motivated by two 500 kV breaker failures resulting from the breakdown of the closing resistor operation mechanism. These occurrences resulted in operative restriction for CEMIG EHV system. The analysis demanded a review of the capability criteria of silicon carbide (Si C) gap arresters, which are still greatly used in CEMIG EHV System, and of the procedures to be applied when carrying out the transient studies. The investigation resulted in the prompt removal of closing resistors from circuit breakers in CEMIG extra-high voltage system generating an economy of approximately U$ 840,00 and an improvement in safety and system reliability. (author) 13 refs., 4 figs., 1 tab.

  11. METHOD OF DETERMINING THE START TIME OF INDUCTION MOTORS IN THE CONTROL OF RESISTOR-THYRISTOR MODULES

    Directory of Open Access Journals (Sweden)

    V.I. Lobov

    2015-08-01

    Full Text Available Purpose. An electric general-purpose drive with asynchronous motor is proposed. For motor control in stator and rotor, circuits used resistors and thyristors. These elements included together in various ways. This allows to get a variety of power converter circuit with resistor-thyristor modules. Methodology. Taking into account the technical requirements for industrial machinery developed an analytical method for determining the run-up controlled induction motor. Formed starting modes by changing the value of the equivalent resistor-thyristor modules. Using logic synthesis and function of thyristors switching to determine the equivalent value of resistor-thyristor modules. Scientific novelty. It lies in the fact that the proposed method of calculation to determine the run-up in the limited amount of transient current and torque of the motor. The total moment of inertia and the static moment of the drive do not have a significant impact on the maximum value of the transient electromagnetic torque. Most of these options affect the transition process, the oscillation frequency of the electromagnetic torque and the motor speed. Practical value. The method used for calculating allows to select the simplest laws of launch control actuator and apply open-loop control system without increasing the cost of the power converter, so it is of practical importance.

  12. Analyzing Broadband Divide in the Farming Sector

    DEFF Research Database (Denmark)

    Jensen, Michael; Gutierrez Lopez, Jose Manuel

    2013-01-01

    Agriculture industry has been evolving for centuries. Currently, the technological development of Internet oriented farming tools allows to increase the productivity and efficiency of this sector. Many of the already available tools and applications require high bandwidth in both directions, upstream and downstream connection. The main constraint is that farms are naturally located in rural areas where the required access broadband data rates are not available. This paper studies the broadband divide in relation to the Danish agricultural sector. Results show how there is an important difference between the broadband availability for farms and the rest of the households/buildings the country. This divide may be slowing down the potential technological development of the farming industry, in order to keep their competitiveness in the market. Therefore, broadband development in rural areas could be one of the points to focus in a near future broadband access plans.

  13. The Digital Divide: A Global View

    Science.gov (United States)

    Ntoko, Alexander

    2011-04-01

    Huge progress was made in bridging the digital divide in first decade of 21^st century. This was largely due to the explosive growth of mobile, which saw numbers rise from under 500 million to over five billion mobile cellular subscriptions in just ten years. With household mobile penetration rates of over 50% even in rural areas of developing countries, we have achieved the dream of bringing all the world's people within reach of communications technology. We must now, however, replicate the mobile miracle for the Internet, and especially broadband, if we are to avoid creating a new broadband breach to replace the digital divide. Three things need to happen for this to be achieved: firstly, broadband needs to be brought to the top of the development agenda; secondly, broadband needs to become much more affordable and thirdly, security needs to be part of the strategy.

  14. Library outreach: addressing Utah's “Digital Divide”

    OpenAIRE

    McCloskey, Kathleen M.

    2000-01-01

    A “Digital Divide” in information and technological literacy exists in Utah between small hospitals and clinics in rural areas and the larger health care institutions in the major urban area of the state. The goals of the outreach program of the Spencer S. Eccles Health Sciences Library at the University of Utah address solutions to this disparity in partnership with the National Network of Libraries of Medicine—Midcontinental Region, the Utah Department of Health, and the Utah Area Health Ed...

  15. Power divider of the MP 10

    International Nuclear Information System (INIS)

    The operation of the MP 10 power divider and resistances (600 megaohms, metal oxide resistances, in the column and in the tube of the MP 10), are investigated. The whole system is used in Vivitron accelerator (Strasbourg, France). The aim of the study is a better understanding of the machine's electrical operation. The resistances are tested under sulphur hexafluoride pressure and under high voltage. The results allowed the characterization of those resistances for use under operating conditions

  16. Bridging the Divide between Science and Journalism

    OpenAIRE

    Marincola Francesco M; Van Eperen Laura; Strohm Jennifer

    2010-01-01

    Abstract There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sourc...

  17. REGENERATIVE GAS TURBINES WITH DIVIDED EXPANSION

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Qvale, Einar Bjørn

    2004-01-01

    Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100 kW. In order to improve the economics of the plants, ways to improve their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficienc...

  18. Inductive voltage divider calibration with sampling method

    Directory of Open Access Journals (Sweden)

    Corminboeuf David

    2014-01-01

    Full Text Available This paper presents an automatic system developed at METAS for the calibration of inductive voltage dividers (IVD. The used method is primary for the n/10 ratio. With the described improvements, the calibration of IVDs has been made easier, faster and more reproducible than with the manual system used before. The uncertainties which can be reached with this new system are 28·10-9 for the in phase and quadrature parts at a frequency of 1 kHz.

  19. Self-organization of divided hierarchy

    Science.gov (United States)

    Odagaki, Takashi; Kitada, Keigo; Omizo, Kenta; Fujie, Ryo

    2015-03-01

    There are two types of extreme form of hierarchy, one is the plutonomy where small fraction of winners and losers and many people in the middle class appear and the other a divided hierarchy where half of population become winners and the remaining half become losers. We study the emergence of the divided hierarchy in a model society which consists of bellicose individuals who always try to fight and fight with the strongest neighbor and pacific individuals who always try not to fight and when necessary fight with the weakest neighbor. In our model society, (1) individuals make random walk on a square lattice, (2) when two individuals encounter they fight each other and (3) the winner deprives wealth from the loser. By a Monte Carlo simulation, we show that there are two transitions when the population density is increased; one is a transition from the egalitarian society to a hierarchical society I where winners, losers and middle classes coexist and the other is a transition from the hierarchical society I to a hierarchical society II where winners and losers exist but no middle classes exist, that is the divided hierarchy. We also show that clusters consisting mostly of bellicose individuals appear in the hierarchical society I.

  20. Conquering the digital divide: Botswana and South Korea digital divide status and interventions

    OpenAIRE

    Nonofo C. Sedimo; Kelvin J. Bwalya; Tanya du Plessis

    2011-01-01

    Background: Botswana is putting in place initiatives towards establishing itself as a knowledgebased economy. Transformation from a resource-based to a knowledge-based economy is partly hinged on innovation, research and development capability, knowledge channels, and the funding of research and development activities.

    Objectives: Bridging the digital divide and narrowing the intra-national divide brings about global informatio...

  1. Prevention of Transformer Saturation at a Black Start by Resistor Insertion of 500kV CB

    Science.gov (United States)

    Nagashima, Hiroshi; Kosugi, Narifumi; Shimojo, Toshikazu; Furukawa, Nobuhiko; Kusunoki, Kiyoshi; Sugeta, Takayuki

    A generating plant can not energize longer transmission lines at once after blackout. The generating plant energize shorter transmission lines firstly, then circuit breaker turns on to connect other transmission lines through the transformer. Transient over voltage oscillation may occur in the transmission lines caused by the resonance of the transmission line. It is reported that the peak voltage exceeds more than 2p.u. when the non-sinusoidal wave voltage caused by saturation in the transformer core excites the resonated transmission line. This paper describes the effect for preventing saturation of transformer by turning on contactors with appropriate resistors before main contactors of the 500kV circuit breaker. The first part presents the mechanism of preventing saturation in the transformer core by pre-resistor insertion of 500kV circuit breaker. The second part presents the expected effect in the actual power system simulated by analytical model using a transients simulation program, EMTP.

  2. A High-Swing OTA with wide Linearity for design of self-tunable linear resistor

    Directory of Open Access Journals (Sweden)

    Nikhil Raj

    2015-09-01

    Full Text Available Low power consumption, long battery life and portability are essential requirements of modern health monitoring products. Operational Trans-conductance Amplifier (OTA operating in sub threshold region is an basic building block for low power health monitoring products design. An modified design of OTA which incorporates better linearity and increased output impedance has been discussed in this paper. The proposed OTA uses High-swing improved-Wilson current mirror for low power and low-frequency applications. The achieved linearity is about ± 1.9 volt and unity gain bandwidth (UGB of 342.30 KHz at power supply of 0.9 volt which makes OTA to consume power in range of nanowatts. The proposed lowvoltage OTA implementation in design of self- tunable linear resistor has been presented in this paper. The circuit implementation has been done using standard 0.18 micron technology provided by TSMC on BSIM3v3 level-53 model parameter and verified results through use of ELDO Simulator.

  3. The SiPM with bulk quenching resistor: progress at NDL and applications in Raman spectroscopy

    International Nuclear Information System (INIS)

    The SiPMs with quenching resistors integrated into bulk epitaxial silicon have been investigated at the Novel Device Laboratory (NDL), Beijing Normal University, China. The aim is to alleviate the conflict between the high photon detection efficiency (PDE) and high APD cell density or dynamic range encountered by conventional SiPM so that this promising detector can be applied where both large dynamic range and high PDE are required simultaneously. We report herein the latest progresses on the SiPM with 104/mm2 micro-cell density and 0.5 mm×0.5 mm, 1 mm×1 mm as well as 20 ?m×1.8 mm effective area, which have been designed and fabricated at NDL. Application of the strip SiPM with a gated photon counting technique on the measurement of TNT Raman spectroscopy is demonstrated, and the feasibility for extending SiPMs in conjunction with Nuclear Instrumentation Modules (NIM) based electronics to the field of ultra-weak spectroscopy is verified.

  4. Development and characterisation of silicon photomultipliers with bulk-integrated quench resistors for future applications in particle and astroparticle physics

    OpenAIRE

    Jendrysik, Christian

    2014-01-01

    This thesis deals with the development and characterisation of a novel silicon photomultiplier concept with bulk-integrated quench resistors. The approach allows the realisation of a free entrance window and high fill factors, which leads to an improvement of the detection efficiency. With first prototype productions a proof of concept was possible. A full characterisation provided promising results, in particular with respect to the photon detection efficiency. By customising the simulation ...

  5. Effects of a parallel resistor on electrical characteristics of a piezoelectric transformer in open-circuit transient state.

    Science.gov (United States)

    Chang, Kuo-Tsai

    2007-01-01

    This paper investigates electrical transient characteristics of a Rosen-type piezoelectric transformer (PT), including maximum voltages, time constants, energy losses and average powers, and their improvements immediately after turning OFF. A parallel resistor connected to both input terminals of the PT is needed to improve the transient characteristics. An equivalent circuit for the PT is first given. Then, an open-circuit voltage, involving a direct current (DC) component and an alternating current (AC) component, and its related energy losses are derived from the equivalent circuit with initial conditions. Moreover, an AC power control system, including a DC-to-AC resonant inverter, a control switch and electronic instruments, is constructed to determine the electrical characteristics of the OFF transient state. Furthermore, the effects of the parallel resistor on the transient characteristics at different parallel resistances are measured. The advantages of adding the parallel resistor also are discussed. From the measured results, the DC time constant is greatly decreased from 9 to 0.04 ms by a 10 k(omega) parallel resistance under open output. PMID:17225805

  6. The Bread Book Multiplying and Dividing

    CERN Document Server

    Hyland, Tony

    2008-01-01

    Bread is an important and useful food and can be bought from stores and small bakeries. Most loaves of bread are shaped like rectangular prisms. Flour, water, yeast, and salt are the key ingredients for making bread. A baker uses a recipe with different measurements of flour and water for each loaf. A baker's dozen is 13 loaves of bread, which is one more than a regular dozen.

  7. Quantitative Measurement of the Digital Divide

    Science.gov (United States)

    Cottrell, Roger

    2007-04-01

    Bandwidth and the Internet infrastructure are the life-blood of the world's knowledge economy, but they are often scarcest where most needed. Measuring the numbers of users of the Internet infrastructure is not easy in developing countries because many people share accounts, use corporate and academic networks, or visit the rapidly growing number of cyber cafes, telecentres and business services. Also measuring the number of users does not take into account the level of use. One valuable indicator for measuring the Internet infrastructure is the international Internet performance of a country or region. One of the major aims of the PingER project is to provide an historical archive of extensive, publicly accessible, up-to-date, measurements, analyses and reports of multiple Internet performance indicators (such as delay, loss, throughput, reachability, and jitter) between sites, countries and regions of the world. This talk will briefly describe the PingER project and then compare and contrast the Internet performance and its trends within and between countries and regions of the world. By means of extensive case studies it will also identify which regions need the greatest attention, together with their major issues and possible approaches to reducing the divide.

  8. Vegetation baseline report : Connacher great divide project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-01

    This baseline report supported an application by Connacher Oil and Gas Ltd. to the Alberta Energy and Utilities Board (EUB) and Alberta Environment (AENV) for the Great Divide Steam Assisted Gravity Drainage (SAGD) Project. The goal of the report was to document the distribution and occurrence of ecosite phases and wetland classes in the project footprint as well as to document the distribution of rare plants; rare plant communities: and intrusive species and old growth communities, including species of management concern. A methodology of the baseline report was presented, including details of mapping and field surveys. Six vegetation types in addition to the disturbed land unit were identified in the project footprint and associated buffer. It was noted that all vegetation types are common for the boreal forest natural regions. Several species of management concern were identified during the spring rare plant survey, including rare bryophytes and non-native or invasive species. Mitigation was identified through a slight shift of the footprint, transplant of appropriate bryophyte species and implementation of a weed management plan. It was noted that results of future surveys for rare plants will be submitted upon completion. It was concluded that the effects of the project on existing vegetation is expected to be low because of the small footprint, prior disturbance history, available mitigation measures and conservation and reclamation planning. 27 refs., 5 tabs., 4 figs.

  9. Bridging the Divide between Science and Journalism

    Directory of Open Access Journals (Sweden)

    Marincola Francesco M

    2010-03-01

    Full Text Available Abstract There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media. Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  10. Can Water Store Charge?

    OpenAIRE

    Ovchinnikova, Kate; Pollack, Gerald H

    2009-01-01

    Previous work from this and other laboratories has demonstrated large pH gradients in water. Established by passing current between immersed electrodes, pH gradients between electrodes were found to disappear slowly, persisting for tens of minutes after the current had been turned off. We find here that these pH gradients reflect a genuine separation of charge: at times well after disconnection of the power supply, current could be drawn through a resistor placed between the charging electrod...

  11. A Compound Generic Quantitative Framework for Measuring Digital Divide

    Directory of Open Access Journals (Sweden)

    Noureldien A. Noureldien

    2014-07-01

    Full Text Available The term digital divide had been used in the literature to conceptualize the gap in using and utilizing information and communication technologies. Digital divide can be identified on different levels such as individuals, groups, societies, organizations and countries. On the other hand, the concept of e-Inclusion is coined to define activities needed to bridge digital divide. One of the most challenging research areas in digital divide that had been a subject for exhaustive studies is measuring digital divide. Researchers have proposed many metrics and indices to measure digital divide. However, most of the proposed measures are bivariate comparisons that reduce measurement to comparisons of Internet penetration rates or alike. This paper proposes a compound generic framework for quantitative measuring of digital divide on the individuals or group level. The proposed framework takes into account the context of the digital divide in each society.

  12. The Digital Divide in the Liberal State: a Canadian Perspective

    OpenAIRE

    Birdsall, William F.

    2000-01-01

    The "digital divide" has emerged as a public policy challenge. This paper examines universal access public policy development in Canada within a North American context and its implications for addressing the digital divide. It concludes that the digital divide will not be eliminated either through public policy or the market due to the liberal public philosophy that is unique to and so strong in North America. The concept of the digital divide represents the dual structure characteristic of N...

  13. Design of shielded voltage divider for impulse voltage measurement

    International Nuclear Information System (INIS)

    The dividers used for the study of the insulation and electric discharge phenomena in high voltage equipments have the problems of the change of response characteristics owing to adjacent bodies and of induced noise. To improve the characteristics, the enclosed type divider shielded with metal has been investigated, and the divider of excellent response has been obtained by adopting the frequency-separating divider system, which is divided into two parts, resistance divider (lower frequency region) and capacitance divider (higher frequency region), for avoiding to degrade the response. Theoretical analysis was carried out in the cases that residual inductance can be neglected or can not be neglected in the small capacitance divider, and that the connecting wires are added. Next, the structure of the divider and the design of the electric field for the divider manufactured on the basis of the theory are described. The response characteristics were measured. The results show that 1 MV impulse voltage can be measured within the response time of 10 ns. Though this divider aims at the impulse voltage, the duration time of which is about that of standard lightning impulse, in view of the heat capacity because of the input resistance of 10.5 k?, it is expected that the divider can be applied to the voltage of longer duration time by increasing the input resistance in future. (Wakatsuki, Y.)

  14. Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors

    International Nuclear Information System (INIS)

    We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300?K) at low and high DC bias voltages (0.001?mV–50?V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

  15. Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors

    Energy Technology Data Exchange (ETDEWEB)

    Aghili Yajadda, Mir Massoud [CSIRO Manufacturing Flagship, P.O. Box 218, Lindfield NSW 2070 (Australia)

    2014-10-21

    We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300 K) at low and high DC bias voltages (0.001 mV–50 V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

  16. Procesamiento analógico a partir de elementos altamente resistivos / Analog Processing based on Quasi-Infinite Resistors

    Scientific Electronic Library Online (English)

    Carlos, Muñiz-Montero; Luis Abraham, Sánchez-Gaspariano; Víctor Hugo, Ponce-Ponce; María Elena, Aguilar-Jáuregui; Osvaldo, Espinosa-Sosa.

    2013-12-01

    Full Text Available El presente trabajo propone una técnica para diseñar, a partir de elementos altamente resistivos, circuitos integrados CMOS analógicos tales como amplificadores compensados en offset, filtros sintonizables de baja frecuencia, espejos de corriente programables y generadores de funciones de membresía. [...] La técnica propuesta incorpora transistores operando en la región de inversión débil para reducir los requerimientos de área y las contribuciones de offset, así como para reducir las componentes de ruido y distorsión, mejorando el compromiso exactitud-velocidad-potencia. Éstas características permiten facilitar el acondicionamiento de señales de baja frecuencia y habilitar el diseño de dispositivos con sintonización multidécada de ganancia y frecuencia. Por otro lado, los circuitos propuestos son atractivos para la implementación analógica de arquitecturas reservadas al ámbito digital, tales como filtros adaptables y sistemas difusos, por mencionar algunos, así como dispositivos de procesamiento y acondicionamiento de señal de alta eficiencia. Se reportan caracterizaciones a partir de simulaciones, mediciones y análisis estadísticos de prototipos diseñados con una tecnología CMOS de 0.5|im de largo de canal, dos capas de polisilicio y tres capas de metal. Los resultados obtenidos concuerdan con aquellos anticipados en el diseño de los circuitos. Abstract in english This work proposes a technique for design of CMOS analog integrated circuits such as offset compensated amplifiers, low-frequency filters, programmable current mirrors and membership function generators, based on high-value (quasi-infinite) resistors. The proposed technique incorporates transistors [...] operating in weak-inversion mode in order to reduce the area requirements and minimize the DC-offset. In addition, improvement on both, noise performance and linearity, are achieved along with an enhanced speed-accuracy-power tradeoff. Those features make easier the processing of low-frequency signals and allow the design of systems with multi-decade tunability of gain and frequency. The presented circuits are attractive for implementation of high-accuracy processors for signal conditioning as well as architectures usually reserved to digital approaches, for instance neural networks, adaptive filters, and neuro-fuzzy systems, to mention a few. Characterization through computer simulations, statistical analysis and experimental measurements of prototypes in a double-poly, three metal layers, 0.5pm CMOS technology are reported. The attained results follow the course anticipated in the design of the circuits.

  17. Development and characterisation of silicon photomultipliers with bulk-integrated quench resistors for future applications in particle and astroparticle physics

    International Nuclear Information System (INIS)

    This thesis deals with the development and characterisation of a novel silicon photomultiplier concept with bulk-integrated quench resistors. The approach allows the realisation of a free entrance window and high fill factors, which leads to an improvement of the detection efficiency. With first prototype productions a proof of concept was possible. A full characterisation provided promising results, in particular with respect to the photon detection efficiency. By customising the simulation tools, a reliable description of the devices was achieved. In addition, conceptual studies of the next device generation demonstrated the possibility of single cell readout, expanding the application range of those detectors to particle tracking.

  18. The effect of pre-ionization by a shunt resistor on the reproducibility of plasma focus x-ray emission

    Science.gov (United States)

    Ahmad, S.; Sadiq, Mehboob; Shafiq, M.; Waheed, A.; Lee, P.; Zakaullah, M.

    2006-08-01

    The effect of pre-ionization by means of a shunt resistor on the x-ray emission of a low energy (1.8 kJ) plasma focus device powered by a 9 µF capacitor bank, charged at 20 kV and giving a peak discharge current of about 175 kA is investigated. Quantrad Si pin-diodes along with a suitable filter are employed as time-resolved x-ray detectors, whereas a multipinhole camera with absorption filters is used for time-integrated analysis. X-ray flux in 4?-geometry is measured as a function of argon filling pressure with and without pre-ionization. It is found that appropriate selection of the shunt resistor increases shot-to-shot reproducibility of the x-ray emission as well as the stability of the pinch filament and broadens the x-ray pulse width. The x-ray emission is also enhanced by (45 ± 5)% at the optimum pressure.

  19. IDENTIFIKASI NILAI HAMBAT JENIS ARANG KAYU, ARANG KULIT MANGGA, DAN ARANG KULIT PISANG: BAHAN ALTERNATIF PENGGANTI RESISTOR FILM KARBON

    Directory of Open Access Journals (Sweden)

    Intan Kusumawati

    2014-05-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui nilai hambat jenis pada arang kayu, arang kulit mangga, dan arang kulit pisang sebagai bahan alternatif pengganti resistor film karbon. Pada penelitian ini dilakukan penumbukkan arang kayu, arang kulit mangga, dan kulit pisang sehingga dihasilkan bubuk arang yang halus melalui proses penyaringan. Setelah itu dilakukan pemampatan arang kayu dalam pipet/sedotan plastik dengan luas permukaan (A = 4,08 x 10-4 cm. Kemudian hambatan diukur menggunakan multimeter dan dilakukan perhitungan hambat jenis arang tersebut. Hasil penelitian menunjukkan bahwa arang kayu (0,73 x 106 m memiliki nilai hambat yang tinggi sehingga hambat jenisnya juga lebih tinggi dibandingkan dengan arang kulit mangga (0,28 x 106  m dan arang kulit pisang (0,24 x 106 m. Hal ini dikarenakan terjadi proses karbonisasi sempurna dalam pembuatan arang kayu. Oleh karena nilai hambatan yang dapat terbaca pada multimeter hanya menggunakan batas skala yang besar (Mega Ohm, maka arang kulit kayu, arang kulit mangga, dan arang kulit pisang hanya dapat dijadikan sebagai bahan alternatif pengganti resistor film karbon dengan ukuran nilai hambatan besar.

  20. A new measurement method of magnetic flux density using magnetorheological fluid characteristics and a variable resistor circuit

    Science.gov (United States)

    Kim, Hwan-Choong; Han, Chulhee; Kim, Pyunghwa; Choi, Seung-Bok

    2015-08-01

    This work proposes a new approach with which to measure the magnetic flux density using the characteristics of magnetorheological fluid (MRF) that is integrated with a variable resistor. For convenience, it is called a magnetorheological fluid variable resistor (MRF-VR) system in this study. The mechanism of the MRF-VR is based on the interaction between ferromagnetic iron particles of the MRF due to an external magnetic field, which causes its electrical resistance to be field dependent. Using this salient principle, the proposed MRF-VR system is constructed with electrodes and MRF, and its performance is demonstrated by evaluating its electrical resistive characteristics such as dimensional influence, response time, hysteresis and frequency response. After evaluating the performance characteristics, a feedback control system with a proportional-integral-derivative (PID) controller is established, and resistance-trajectory control experiments are carried out. Based on this MRF-VR system, a magnetic field-sensing system is constructed using a Wheatstone bridge circuit, and a polynomial model for calculating the magnetic flux density is formulated from the measured voltage. Finally, the accuracy and effectiveness of the proposed sensing system associated with the empirical polynomial model is successfully verified by comparing the calculated values of magnetic flux density with those measured by a commercial tesla meter.

  1. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  2. OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. I.; Kim, J. L.; Pradhan, A. S.; Chang, I.; Kim, B. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Optically stimulated luminescence (OSL) and thermoluminescence (TL) of ubiquitous materials continue to draw wider attention for individual dosimetry in nuclear and radiation accidents. Use of ubiquitous objects for radiation dosimetry is preferred because the affected persons in such unexpected events are usually not covered by personal dosimetry services and do not carry personal dosimeters. Often accident sites do not have area monitoring system in place. As the main concern of the dosimetry is health effects, a quick distinction of level of exposures of the affected persons for the required medical care becomes important in all accidents involving radiation. Both in large scale nuclear accidents such Fukushima, Chernobyl or Hiroshima and Nagasaki where large population around the accident site get exposed to radiation (evacuation is based on doses) and in smaller but panicky events, such as misuse of radiological exposure device (RED), radiological dispersive device (RDD: 'Dirty Bomb'), improvised nuclear device (IND) and deliberate dispersal of radioactive contaminants, a need for an ubiquitous personal dosimeter is well recognized. As biological dosimetry systems are yet to become viable for measurements of doses with required accuracy and speed, use of physical dosimeters is often explored. Among the various types of physical dosimetry systems, use of TL and OSL by processing common material such as bricks or tiles and measuring the doses cumulated for long periods of time has already become an accepted tool for large scale nuclear accidents such as Hiroshima and Nagasaki or Chernobyl involving higher doses. In the other potential cases of unexpected situations where the doses encountered could be much lower (even to escape the range of remotely installed area monitors), the need to measure even the low doses in shortest possible time becomes important. It is often realized that in such situations, the main problem could become the panic at the work place and in the public rather than actual health hazard due to radiation exposure. Therefore, a quick demonstration of measurement of doses following the accident is needed to reassure those receiving insignificant or low level of exposures that they are quite safe and need no treatment. This confidence building also becomes an important aspect of dosimetry. As the ranges of doses which could be encountered in such situations may vary from the background level to significantly high doses depending on the type of accident / incident and the location of personnel, it becomes important that the techniques used in retrospective dosimetry should be very sensitive and should be able to measure doses in a wide range from background level to several Gy. More recently, with the increasing apprehensions of nuclear terrorism / dirty bomb, research and developments in retrospective dosimetry has gained a new momentum the world over. Among the TL and OSL sensitive materials, the extraction and the processing of the materials from bricks and roof tiles is a very time consuming process and gives indirect estimate of individual doses. On the other hand, TL and OSL properties of components of electronic devices mobile phones, i-pods, black-berries, mp3 players and USB sticks containing ceramics with luminescence properties (e.g resistors, capacitors, resonators, antenna switches, transistors etc.) and chip cards containing silica epoxy (e.g. credit cards, bank cards, social security card, telephone card, SIM cards, ID cards e.g) are being considered very attractive and being evaluated. In this study, the TL and OSL properties of the electronic components of mobile phones are investigated and dose recovery potential is evaluated with a presumption that a mobile phone has become a part of body belongings masses of almost ages

  3. OSL and TL of Resistors of Mobile Phones for Retrospective Accident Dosimetry

    International Nuclear Information System (INIS)

    Optically stimulated luminescence (OSL) and thermoluminescence (TL) of ubiquitous materials continue to draw wider attention for individual dosimetry in nuclear and radiation accidents. Use of ubiquitous objects for radiation dosimetry is preferred because the affected persons in such unexpected events are usually not covered by personal dosimetry services and do not carry personal dosimeters. Often accident sites do not have area monitoring system in place. As the main concern of the dosimetry is health effects, a quick distinction of level of exposures of the affected persons for the required medical care becomes important in all accidents involving radiation. Both in large scale nuclear accidents such Fukushima, Chernobyl or Hiroshima and Nagasaki where large population around the accident site get exposed to radiation (evacuation is based on doses) and in smaller but panicky events, such as misuse of radiological exposure device (RED), radiological dispersive device (RDD: 'Dirty Bomb'), improvised nuclear device (IND) and deliberate dispersal of radioactive contaminants, a need for an ubiquitous personal dosimeter is well recognized. As biological dosimetry systems are yet to become viable for measurements of doses with required accuracy and speed, use of physical dosimeters is often explored. Among the various types of physical dosimetry systems, use of TL and OSL by processing common material such as bricks or tiles and measuring the doses cumulated for long periods of time has already become an accepted tool for large scale nuclear accidents such as Hiroshima and Nagasaki or Chernobyl involving higher doses. In the other potential cases of unexpected situations where the doses encountered could be much lower (even to escape the range of remotely installed area monitors), the need to measure even the low doses in shortest possible time becomes important. It is often realized that in such situations, the main problem could become the panic at the work place and in the public rather than actual health hazard due to radiation exposure. Therefore, a quick demonstration of measurement of doses following the accident is needed to reassure those receiving insignificant or low level of exposures that they are quite safe and need no treatment. This confidence building also becomes an important aspect of dosimetry. As the ranges of doses which could be encountered in such situations may vary from the background level to significantly high doses depending on the type of accident / incident and the location of personnel, it becomes important that the techniques used in retrospective dosimetry should be very sensitive and should be able to measure doses in a wide range from background level to several Gy. More recently, with the increasing apprehensions of nuclear terrorism / dirty bomb, research and developments in retrospective dosimetry has gained a new momentum the world over. Among the TL and OSL sensitive materials, the extraction and the processing of the materials from bricks and roof tiles is a very time consuming process and gives indirect estimate of individual doses. On the other hand, TL and OSL properties of components of electronic devices mobile phones, i-pods, black-berries, mp3 players and USB sticks containing ceramics with luminescence properties (e.g resistors, capacitors, resonators, antenna switches, transistors etc.) and chip cards containing silica epoxy (e.g. credit cards, bank cards, social security card, telephone card, SIM cards, ID cards e.g) are being considered very attractive and being evaluated. In this study, the TL and OSL properties of the electronic components of mobile phones are investigated and dose recovery potential is evaluated with a presumption that a mobile phone has become a part of body belongings masses of almost ages

  4. Digital Divide amongst Urban Youths in Malaysia – Myth or Reality?

    OpenAIRE

    Patrick C-H Soh; Yap Liang Yan; Tze San Ong; Boon Heng Teh

    2012-01-01

    The Digital Divide is an important issue with serious consequences, both for the individuals affected and society. With 90% of youths in urban areas using the Internet, there is a myth that the Digital Divide no longer exists amongst urban youths. Based on a random survey of 1639 youths, this study analyses the possibility of a digital divide along ethnic lines in Malaysia.. Findings indicate there are significant ethnic-based differences in home PC ownership and Internet connection. There ar...

  5. Layer dividing and zone dividing of physical property of crust and deep structure in Jiangxi province

    International Nuclear Information System (INIS)

    On the base of summing experiences both at home and abroad, the Bugar gravitative anomalies are studied by major means of data processing. According to the anomalous character, three layer crust models (surface layer, middle layer in region and material layer under crust) are built up, depth of upper and bottom surfaces for every layer is calculated quantitatively, their varied characters of depth are studied and deep geological tectonics are outlined. The 'density' and 'mass' of every layer are calculated, and according to these two parameters, the shallow geological tectonics are researched. The relation-factor R between the surface altitude and Bugar gravitative anomalies are calculated and the stable or unstable crust zones are divided. The favorable mine zones for uranium deposit in Jiangxi Province are outlined

  6. Effects of resistors and capacitors inserted between wires and chip bonding pads on current-voltage characteristics of series junction arrays

    International Nuclear Information System (INIS)

    Series Nb/AlO x/Nb junction array circuits are commonly used for evaluation of a critical current (I c) spread as an important parameter on Nb-based LSI chips. We present a junction array circuit suitable for accurate evaluation of the spread. The circuit has a tolerance for the I c suppression caused by external noises and synchronous switching which are often observed in measurements. Key elements of the circuit are the low value resistors, large value capacitors, and high value resistors inserted between wires and chip bonding pads. This paper describes effects of these key elements on current-voltage characteristics of junction arrays

  7. Dividir para reinar / Diviser pour régner / Divide and conquer / Divide y vencerás

    Scientific Electronic Library Online (English)

    Teresa Vaz, Martins; Raúl, Toral.

    2012-06-01

    Full Text Available O objectivo deste artigo é apresentar brevemente a Sociofísica, uma disciplina que, nas últimas décadas, se tem vindo a desenvolver na fronteira entre a Física e as ciências sociais. Como ilustração da sua abordagem, iremos rever alguns modelos de formação de opinião, incidindo nas condições em que [...] uma sociedade é mais sensível à penetração de uma mensagem externa. Nomeadamente, iremos ver que é mais fácil uma mensagem ser consensualmente aceite numa sociedade caracterizada por conflitos - o que recorda a antiga máxima “dividir para reinar”. Concluiremos, sugerindo que a construção deste novo campo do saber requer uma colaboração entre sociólogos e físicos, que vá mais além de uma simples justaposição de conhecimentos. Abstract in spanish El objectivo de este trabajo es presentar brevemente la Sociofísica, una disciplina que en las últimas décadas se ha venido a desarrollar en la frontera entre la física y las ciencias sociales. Cómo ejemplo de su enfoque, se revisan algunos modelos de formación de opinión, centrándose en las condici [...] ones en que una sociedad es más sensible a la penetración de un mensaje externo. En particular, vemos que el mensaje es más fácilmente aceptado en una sociedad caracterizada por el conflicto, lo que nos acuerda el antiguo dicho latino, “divide y vencerás”. Concluimos sugiriendo que la construcción de este nuevo campo del conocimiento requiere una colaboración entre los sociólogos y físicos, que va más allá de una simple yuxtaposición de conocimientos. Abstract in english The aim of this paper is to briefly present Sociophysics, a discipline that in recent decades has been emerging on the borders between Physics and the Social Sciences. As an illustration of its approach, we will review some opinion formation models, focusing on the conditions under which a society i [...] s more sensitive to the penetration of an external message. In particular, we will see that it is easier for a message to be commonly accepted in a society characterized by conflicts - which recalls the old maxim “divide and conquer”. We conclude by suggesting that the construction of this new field of knowledge requires a union between sociologists and physicists that goes beyond a simple juxtaposition of knowledge.

  8. The Digital Divide: The Special Case of Gender

    Science.gov (United States)

    Cooper, J.

    2006-01-01

    This paper examines the evidence for the digital divide based on gender. An overview of research published in the last 20 years draws to the conclusion that females are at a disadvantage relative to men when learning about computers or learning other material with the aid of computer-assisted software. The evidence shows that the digital divide…

  9. Prospective memory: effects of divided attention on spontaneous retrieval.

    Science.gov (United States)

    Harrison, Tyler L; Mullet, Hillary G; Whiffen, Katie N; Ousterhout, Hunter; Einstein, Gilles O

    2014-02-01

    We examined the effects of divided attention on the spontaneous retrieval of a prospective memory intention. Participants performed an ongoing lexical decision task with an embedded prospective memory demand, and also performed a divided-attention task during some segments of lexical decision trials. In all experiments, monitoring was highly discouraged, and we observed no evidence that participants engaged monitoring processes. In Experiment 1, performing a moderately demanding divided-attention task (a digit detection task) did not affect prospective memory performance. In Experiment 2, performing a more challenging divided-attention task (random number generation) impaired prospective memory. Experiment 3 showed that this impairment was eliminated when the prospective memory cue was perceptually salient. Taken together, the results indicate that spontaneous retrieval is not automatic and that challenging divided-attention tasks interfere with spontaneous retrieval and not with the execution of a retrieved intention. PMID:24046252

  10. Prediction of multiple resonance characteristics by an extended resistor-inductor-capacitor circuit model for plasmonic metamaterials absorbers in infrared.

    Science.gov (United States)

    Xu, Xiaolun; Li, Yongqian; Wang, Binbin; Zhou, Zili

    2015-10-01

    The resonance characteristics of plasmonic metamaterials absorbers (PMAs) are strongly dependent on geometric parameters. A resistor-inductor-capacitor (RLC) circuit model has been extended to predict the resonance wavelengths and the bandwidths of multiple magnetic polaritons modes in PMAs. For a typical metallic-dielectric-metallic structure absorber working in the infrared region, the developed model describes the correlation between the resonance characteristics and the dimensional sizes. In particular, the RLC model is suitable for not only the fundamental resonance mode, but also for the second- and third-order resonance modes. The prediction of the resonance characteristics agrees fairly well with those calculated by the finite-difference time-domain simulation and the experimental results. The developed RLC model enables the facilitation of designing multi-band PMAs for infrared radiation detectors and thermal emitters. PMID:26421549

  11. Integrated one diode-one resistor architecture in nanopillar SiOx resistive switching memory by nanosphere lithography.

    Science.gov (United States)

    Ji, Li; Chang, Yao-Feng; Fowler, Burt; Chen, Ying-Chen; Tsai, Tsung-Ming; Chang, Kuan-Chang; Chen, Min-Chen; Chang, Ting-Chang; Sze, Simon M; Yu, Edward T; Lee, Jack C

    2014-02-12

    We report on a highly compact, one diode-one resistor (1D-1R) nanopillar device architecture for SiOx-based ReRAM fabricated using nanosphere lithography (NSL). The intrinsic SiOx-based resistive switching element and Si diode are self-aligned on an epitaxial silicon wafer using NSL and a deep-Si-etch process without conventional photolithography. AC-pulse response in 50 ns regime, multibit operation, and good reliability are demonstrated. The NSL process provides a fast and economical approach to large-scale patterning of high-density 1D-1R ReRAM with good potential for use in future applications. PMID:24369783

  12. Social Support Quality in Internet Based Information and Communication: From "Digital Divide" to "Voice Divide"

    Directory of Open Access Journals (Sweden)

    2004-05-01

    Full Text Available National and international studies demonstrate that the number of teenagers using the inter-net increases. But even though they actually do have access from different places to the in-formation and communication pool of the internet, there is evidence that the ways in which teenagers use the net - regarding the scope and frequency in which services are used as well as the preferences for different contents of these services - differ significantly in relation to socio-economic status, education, and gender. The results of the regarding empirical studies may be summarised as such: teenager with low (formal education especially use internet services embracing 'entertainment, play and fun' while higher educated teenagers (also prefer intellectually more demanding and particularly services supplying a greater variety of communicative and informative activities. More generally, pedagogical and sociological studies investigating "digital divide" in a dif-ferentiated and sophisticated way - i.e. not only in terms of differences between those who do have access to the Internet and those who do not - suggest that the internet is no space beyond 'social reality' (e.g. DiMaggio & Hargittai 2001, 2003; Vogelgesang, 2002; Welling, 2003. Different modes of utilisation, that structure the internet as a social space are primarily a specific contextualisation of the latter - and thus, the opportunities and constraints in virtual world of the internet are not less than those in the 'real world' related to unequal distribu-tions of material, social and cultural resources as well as social embeddings of the actors involved. This fact of inequality is also true regarding the outcomes of using the internet. Empirical and theoretical results concerning forms and processes of networking and commu-nity building - i.e. sociability in the internet, as well as the social embeddings of the users which are mediated through the internet - suggest that net based communication and infor-mation processes may entail the resource 'social support'. Thus, with reference to social work and the task of compensating the reproduction of social disadvantages - whether they are medial or not - the ways in which teenagers get access to and utilize net based social sup-port are to be analysed.

  13. Continental Divide of the United States - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer portrays the Continental Divide of the United States. The map layer was created by extracting Hydrologic Unit Boundary line features from an existing...

  14. Digital Divide amongst Urban Youths in Malaysia – Myth or Reality?

    Directory of Open Access Journals (Sweden)

    Patrick C-H Soh

    2012-12-01

    Full Text Available The Digital Divide is an important issue with serious consequences, both for the individuals affected and society. With 90% of youths in urban areas using the Internet, there is a myth that the Digital Divide no longer exists amongst urban youths. Based on a random survey of 1639 youths, this study analyses the possibility of a digital divide along ethnic lines in Malaysia.. Findings indicate there are significant ethnic-based differences in home PC ownership and Internet connection. There are further concerns that the digital divide is further widening because of the quantity and quality of access. Multivariate analysis reveals that Chinese youths are online for twice the duration of Malays and Indians. However, higher Internet usage may be a two-edged sword as higher Internet use are intertwined with higher risks and negative activities such as violent games, pornography, and gambling. The article also discusses various means to mitigate the risks of Internet usage.

  15. Narrowing the Digital Divide in Low-Income, Urban Communities

    Science.gov (United States)

    Norris, Daniel T.; Conceicao, Simone

    2004-01-01

    The digital divide is leaving millions disenfranchised from the opportunity to use technology to change their lives and to participate fully in democracy, in their own communities, and in today's job market.

  16. Hyperglycemia diverts dividing stem cells to pathological adipogenesis

    OpenAIRE

    Hascall, Vincent; Wang, AiMin

    2014-01-01

    This commentary proposes a mechanism for why murine diabetic adipose tissue contains very few remaining stem cells compared with normal adipose tissue. The mechanism involves the diversion of stem cells to pathological adipocytes when they divide in hyperglycemia.

  17. Annan warns of 'content divide' between rich and poor

    CERN Multimedia

    Dickson, D

    2003-01-01

    "The Secretary-General of the United Nations, Kofi Annan, warned today (10 December) that a "content divide" is threatening to deprive developing countries of the full benefits offered by information and communications technologies (ICTs)" (1 page)

  18. THE DIGITAL DIVIDE: HOW WIDE AND HOW DEEP?

    OpenAIRE

    Schloman, Barbara F

    2004-01-01

    The complexity of the issues that make up the digital divide problem is better understood today. It is no longer sufficient to see it simply as a disparity of access to computer technology. Rather, there is recognition that having meaningful support for using the technology is also an essential ingredient for getting online. The digital divide is a global problem, but even in the technology rich United States the situation is troubling. Recent studies have shown that within the United States,...

  19. Digital Divide between Teachers and Students in Urban Bangladesh

    OpenAIRE

    Khalid, Md. Saifuddin

    2012-01-01

    Telecom boom since 2000 and ‘Digital Bangladesh’ campaign since late 2008 created significant nationwide hype, resulting rapid increase in the use of digital devices. While studies are being conducted to use the ability of “power users of technology” for reducing digital divide, there is hardly any data available on them in Bangladesh context. A study was conducted to study the digital divide and ICT usage pattern among the urban students and teachers of schools and colleges in Dhaka, the cap...

  20. Wireless Technologies Bridging the Digital Divide in Education

    OpenAIRE

    Gerard Smyth

    2006-01-01

    The objective of this paper is to demonstrate how the latest wireless standards and technologies may overcome the digital divide in education in the developed and developing worlds. The concept of the digital divide is discussed in the traditional socio-economic sense and expanded in terms of the learner's location, age, culture and background. It is important that we understand the full extent and complexities of this division if we are to effectively bridge it. Why and how the digital div...

  1. Afterword. Internet Freedom, Nuanced Digital Divide, and the Internet Craftsman

    OpenAIRE

    Meinrath, Sascha D.; Losey, James; Lennett, Benjamin

    2013-01-01

    This book provides an in-depth comparative analysis of inequality and the stratification of the digital sphere. Grounded in classical sociological theories of inequality, as well as empirical evidence, this book defines 'the digital divide' as the unequal access and utility of internet communications technologies and explores how it has the potential to replicate existing social inequalities, as well as create new forms of stratification. The Digital Divide examines how various demographic an...

  2. Digital Divide between Teachers and Students in Urban Bangladesh

    DEFF Research Database (Denmark)

    Khalid, Md. Saifuddin

    2011-01-01

    Telecom boom since 2000 and ‘Digital Bangladesh’ campaign since late 2008 created significant nationwide hype, resulting rapid increase in the use of digital devices. While studies are being conducted to use the ability of “power users of technology” for reducing digital divide, there is hardly any data available on them in Bangladesh context. A study was conducted to study the digital divide and ICT usage pattern among the urban students and teachers of schools and colleges in Dhaka, the capita...

  3. Generation of five phase-locked harmonics by implementing a divide-by-three optical frequency divider

    CERN Document Server

    Suhaimi, Nurul Sheeda; Gavara, Trivikramarao; Nakagawa, Ken'ichi; Hong, Feng Lei; Katsuragawa, Masayuki

    2015-01-01

    We report the generation of five phase-locked harmonics, f_1: 2403 nm, f_2: 1201 nm, f_3: 801 nm, f_4: 600 nm, and f_5: 480 nm with an exact frequency ratio of 1 : 2 : 3 : 4 : 5 by implementing a divide-by-three optical-frequency divider in the high harmonic generation process. All five harmonics are generated coaxially with high phase coherence in time and space, which are applicable for various practical uses.

  4. Behavior of 1?? resistors at frequencies below 1?Hz and the problem of assigning a dc value

    Science.gov (United States)

    Fletcher, Nick; Götz, Martin; Rolland, Benjamin; Pesel, Eckart

    2015-08-01

    This paper presents a systematic study of the effects of reversals of current polarity on 1?? standard resistors. A selection of 1?? standards were measured on a dc cryogenic current comparator bridge and also on an ac current comparator bridge operating at 1?Hz. We find that the apparent 4 terminal resistance depends strongly on the dc reversal rate, in one case showing a variation of more than 0.1???/? for cycle times between 10?s and 1000?s. Even in the best cases, effects of at least 0.01???/? are present. Furthermore, the assumption that the apparent resistance value converges to a limiting value for long waiting times after reversal is not always upheld, making it difficult to quote a simple dc value. Existing models of Peltier heating at wire junctions do not completely explain our observations. The problems presented have been the limiting factor for 1?? measurements as part of a recent on-site comparison of quantum Hall effect resistance standards.

  5. The bounds of the set of equivalent resistances of n equal resistors combined in series and in parallel

    CERN Document Server

    Khan, Sameen Ahmed

    2010-01-01

    The order of the set of equivalent resistances, A(n) of n equal resistors combined in series and in parallel has been traditionally addressed computationally, for n up to 22. For larger n there have been constraints of computer memory. Here, we present an analytical approach using the Farey sequence with Fibonacci numbers as its argument. The approximate formula, A(n) ~ 2.55^n, obtained from the computational data up to n = 22 is consistent with the strict upper bound, A(n) ~ 2.618^n, presented here. It is further shown that the Farey sequence approach, developed for the A(n) is applicable to configurations other than the series and/or parallel, namely the bridge circuits and non-planar circuits. Expressions describing set theoretic relations among the sets A(n) are presented in detail. For completeness, programs to generate the various integer sequences occurring in this study, using the symbolic computer language MATHEMATCA, are also presented.

  6. Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory

    International Nuclear Information System (INIS)

    We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott’s conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory. -- Highlights: • Alternative derivation of certain trigonometrical sums of the chiral Potts model are given. • Generalization of these trigonometrical sums satisfy recursion formulas. • The dimension of the space of conformal blocks may be computed from these recursions. • Exact corner-to-corner resistance, the Kirchhoff index of 2×N are given

  7. Transformer-based design techniques for oscillators and frequency dividers

    CERN Document Server

    Luong, Howard Cam

    2016-01-01

    This book provides in-depth coverage of transformer-based design techniques that enable CMOS oscillators and frequency dividers to achieve state-of-the-art performance.  Design, optimization, and measured performance of oscillators and frequency dividers for different applications are discussed in detail, focusing on not only ultra-low supply voltage but also ultra-wide frequency tuning range and locking range.  This book will be an invaluable reference for anyone working or interested in CMOS radio-frequency or mm-Wave integrated circuits and systems.

  8. Bruce NGS A Unit 4 preheater divider plate failure

    International Nuclear Information System (INIS)

    On May 19, 1995, without any prior operational indications, Bruce A discovered preheater divider plate damage in Unit 4 that had the potential to have a major impact on the continued safe operation of the station. Further investigations indicated that Unit 4 may have been operating with this damage for as long as ten years. In the two months following the discovery, Bruce A has procured and replaced the 4 divider plates, located most of the missing pieces, retrieved pieces from the PHT system, investigated historical operational information, performed detailed analytical investigations, investigated root cause, performed in-situ and mock-up testing, updated operational procedures and installed DP monitoring equipment

  9. Google and the digital divide the bias of online knowledge

    CERN Document Server

    Segev, Elad

    2010-01-01

    Beneficial to scholars and students in the fields of media and communication, politics and technology, this book outlines the significant role of search engines in general and Google in particular in widening the digital divide between individuals, organisations and states. It uses innovative methods and research approaches to assess and illustrate the digital divide by comparing the popular search queries in Google and Yahoo in different countries as well as analysing the various biases in Google News and Google Earth. The different studies developed and presented in this book provide various

  10. Conduction mechanisms and 1/f noise in thick-film resistors with Pb3Rh7O15 and Pb2Ru2O7

    International Nuclear Information System (INIS)

    Thick-film resistors with Pb3Rh7015 and Pb2Ru207 as conductors are considered. These compounds are chemically stable during the firing process of the resistors. The variation of sheet resistivity R/sub D'Alembertian/ with volume fraction conductor follows a simple power law. This result cannot be explained by percolation theory in its simple form. The conductivity is found to be independent of frequency up to 10 GHz. In both cases a small positive Hall coefficient is observed which is interpreted as being due to mixed electron and hole conduction. Finally the 1/f noise is considered, and is found to vary approximately linearly with R/sub D'Alembertian/. A theoretical model for the 1/f noise in thick-film resistors is presented that accounts for this linear relationship. The observed deviations from linearity indicate that probably tunneling through barriers at the interfaces between the conducting grains is an important factor in determining the conduction

  11. Dividing Attention Lowers Children's but Increases Adults' False Memories

    Science.gov (United States)

    Otgaar, Henry; Peters, Maarten; Howe, Mark L.

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

  12. The Digital Divide and Its Impact on Academic Performance

    Science.gov (United States)

    Sun, Jerry Chih-Yuan; Metros, Susan E.

    2011-01-01

    The purpose of this article is to explore issues of the digital divide and its impact on academic performance. Research shows that proper use of technology by students increases their academic performance outcomes. In the literature review section, the authors review articles and theories based on Bennett's (2001) societal equity framework. The…

  13. Multiple-Size Divide-and-Conquer Recurrences

    OpenAIRE

    Kao, Ming-Yang

    2001-01-01

    This short note reports a master theorem on tight asymptotic solutions to divide-and-conquer recurrences with more than one recursive term: for example, T(n) = 1/4 T(n/16) + 1/3 T(3n/5) + 4 T(n/100) + 10 T(n/300) + n^2.

  14. New Literacies at the Digital Divide: American Indian Community Computing

    Science.gov (United States)

    Betts, J. David

    2009-01-01

    This study is about a community computing lab established by a U.S. Department of Commerce grant to bridge the Digital Divide in a rural Arizona American Indian community, a project called "Native Connection" (a pseudonym). This paper describes the process of integrating new literacies associated with a high-tech computer lab into the life of a…

  15. Area and Power Optimization of Flexible Multiband Divider

    Directory of Open Access Journals (Sweden)

    R.Naveenkumar

    2013-12-01

    Full Text Available The demand for lower cost, lower power, and multiband RF circuits increased in conjunction with need of higher level of integration. In this project a low-power single-phase clock multiband flexible divider for Bluetooth, Zigbee, and Network standard’s 802.15.4 and 802.11 a/b/g Wireless LAN frequency synthesizers is proposed based on pulse-swallow topology and is implemented. The frequency synthesizer, usually implemented by a phase-locked loop (PLL, is one of the power-hungry blocks in the RF front-end and the first-stage frequency divider consumes a large portion of power in a frequency synthesizer. The proposed prescaler based approach reduces the area and power significantly. The multiband divider consists of a proposed wideband multi modulus 32/33/47/48 prescaler and an improved bit-cell for swallow (S counter and can divide the frequencies in the three bands of 2.41–2.483 GHz, 5.14–5.30 GHz, and 5.715–5.815 GHz with a resolution selectable from 1 to 25 MHz The proposed multiband flexible divider is silicon verified and consumes power of 0.96 and 2.2 mw in 2.3-and 5-GHz bands, respectively, when operated at 1.8-V power supply. The proposed prescaler is achieved by without using any additional flip flops. It gives a solution to the low power PLL synthesizers for wide range of communication applications.

  16. Water

    Science.gov (United States)

    ... How does lead get into my tap water? Measures taken during the last two decades have greatly reduced exposures to lead in tap water. These measures include actions taken under the requirements of the 1986 and 1996 ...

  17. Water

    Science.gov (United States)

    ... water pollution How to protect yourself from water pollution Air Chemicals Noise Quizzes Links to more information girlshealth glossary girlshealth. ... usually in the water, made up of one cell, and lack true stems, roots, and leaves. Spills ... Source: U.S. Environmental Protection Agency Here are some ...

  18. Thermosetting polyimide resin matrix composites with interpenetrating polymer networks for precision foil resistor chips based on special mechanical performance requirements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.Y., E-mail: wxy@tju.edu.cn [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Ma, J.X.; Li, C.G. [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Wang, H.X. [ZHENGHE electronics Co., Ltd, Jining 272023 (China)

    2014-04-01

    Highlights: • Macromolecular materials were chosen to modify thermosetting polyimide (TSPI). • The formation of IPN structure in TSPI composite polymers was discussed. • The special mechanical properties required were the main study object. • The desired candidate materials should have proper hardness and toughness. • The specific mechanical data are quantitatively determined by experiments. - Abstract: Based on interpenetrating networks (IPNs) different macromolecular materials such as epoxy, phenolic, and silicone resin were chosen to modify thermosetting polyimide (TSPI) resin to solve the lack of performance when used for protecting precision foil resistor chips. Copolymerization modification, controlled at curing stage, was used to prepare TSPI composites considering both performance and process requirements. The mechanical properties related to trimming process were mainly studied due to the special requirements of the regularity of scratch edges caused by a tungsten needle. The analysis on scratch edges reveals that the generation and propagation of microcracks caused by scratching together with crack closure effect may lead to regular scratch traces. Experiments show that the elongation at break of TSPI composites is the main reason that determines the special mechanical properties. The desired candidate materials should have proper hardness and toughness, and the specific mechanical data are that the mean elongation at break and tensile strength of polymer materials are in the range of 9.2–10.4% and 100–107 MPa, respectively. Possible reasons for the effect of the modifiers chosen on TSPI polymers, the reaction mechanisms on modified TSPI resin and the IPN structure in TSPI composite polymers were discussed based on IR and TG analysis.

  19. Thermosetting polyimide resin matrix composites with interpenetrating polymer networks for precision foil resistor chips based on special mechanical performance requirements

    International Nuclear Information System (INIS)

    Highlights: • Macromolecular materials were chosen to modify thermosetting polyimide (TSPI). • The formation of IPN structure in TSPI composite polymers was discussed. • The special mechanical properties required were the main study object. • The desired candidate materials should have proper hardness and toughness. • The specific mechanical data are quantitatively determined by experiments. - Abstract: Based on interpenetrating networks (IPNs) different macromolecular materials such as epoxy, phenolic, and silicone resin were chosen to modify thermosetting polyimide (TSPI) resin to solve the lack of performance when used for protecting precision foil resistor chips. Copolymerization modification, controlled at curing stage, was used to prepare TSPI composites considering both performance and process requirements. The mechanical properties related to trimming process were mainly studied due to the special requirements of the regularity of scratch edges caused by a tungsten needle. The analysis on scratch edges reveals that the generation and propagation of microcracks caused by scratching together with crack closure effect may lead to regular scratch traces. Experiments show that the elongation at break of TSPI composites is the main reason that determines the special mechanical properties. The desired candidate materials should have proper hardness and toughness, and the specific mechanical data are that the mean elongation at break and tensile strength of polymer materials are in the range of 9.2–10.4% and 100–107 MPa, respectively. Possible reasons for the effect of the modifiers chosen on TSPI polymers, the reaction mechanisms on modified TSPI resin and the IPN structure in TSPI composite polymers were discussed based on IR and TG analysis

  20. SIW based multilayer transition and power divider in LTCC technology

    KAUST Repository

    Abuzaid, Hattan

    2013-06-01

    A multilayer transition and balanced power divider are presented for millimeter-wave system-on-package (SoP). These two components operate at Ka-band and exploit the substrate integrate waveguide (SIW) technology with its shielding characteristics and the Low-temperature co-fired ceramics (LTCC) technology for its high density integration. A coupling slot has been used to perform vertical integration, which can be easily optimized through its length. The measured input return loss within the bandwidth of interest (32 GHz-38 GHz) is less than -15 dB and -18 dB for the multilayer transition and the power divider, respectively. The lateral dimensions of a multilayer system, such as a feed network of an array, can be greatly reduced by employing these 3D slot-coupled components. © 2013 IEEE.

  1. Climate Change and North-South Divide. Between and Within

    International Nuclear Information System (INIS)

    The traditional North-South divide has persisted through out the negotiations on climate change. Divergent state interests made striking a right balance between development and environmental protection an elusive endeavor as negotiators were striving to adopt a global climate regime. Four principles of international environmental law are of particular concern: the principle of common but differentiated responsibilities, the principle of equity, the precautionary principle, and the principle of sustainable development. With economic development being the overriding priority in developing countries, the negotiations leading to the Kyoto Protocol tend to prove that principles could be interpreted in different ways to fit particular interests. This study explains the confrontations between the North and the South and argues that climate change has by far strengthened the North-South divide both between and within. Accordingly, it concludes that there is a need to devise new principles

  2. Ecuador, the Digital Divide and Small Tourism Enterprises

    Directory of Open Access Journals (Sweden)

    Stan Karanasios

    2014-09-01

    Full Text Available This article explores the digital divide from the perspective of Ecuadorian small tourism enterprises. Ecuador’s ICT environment has been described as underdeveloped, obsolete, and expensive to use. There is also a serious shortage of ICT related human capital. Given these stumbling blocks, this article seeks to identify how small tourism operators have managed to adopt the Internet. Adopting a qualitative approach, field interviews were conducted with tourism enterprises across rural, semi-rural, and metropolitan areas of Ecuador. This article adds to our understanding of the digital divide, especially from the point of view of small tourism enterprises, and serves as an example to other small tourism enterprises in developing countries seeking to adopt the Internet.

  3. The 'Digital Divide' Among Financially Disadvantaged Families in Australia

    OpenAIRE

    McLaren, Jennifer; Zappala, Gianni

    2002-01-01

    Despite figures suggesting that Australia is a high consumer of information and communication technologies (ICT), it is well documented that the pattern of this consumption is not spread evenly across the population; a 'digital divide' exists. In general, research suggests that people from higher socioeconomic backgrounds have greater access to ICT compared to those from lower socioeconomic backgrounds. A less well-researched area is the factors that may influence ICT access and usage within ...

  4. Job quality in Europe: the North-South divide

    OpenAIRE

    Cerdeira, Maria da Conceição; Kovács, Ilona

    2008-01-01

    This paper examines the job quality in Europe. It is based on the results of the Fourth European Foundation Survey on working conditions covering different dimensions including work organisation, job content, autonomy at work, aspects of worker dignity, working time and work-life balance, working conditions and safety in the workplace. The results point to the existence of great diversity in the job quality across Europe and the north-south divide. The job quality differences are related to t...

  5. Is the digital divide between young and elderly people increasing?

    OpenAIRE

    Paul, Gerd; Stegbauer, Christian

    2005-01-01

    Elderly people still play a minor role in research on information needs and usage patterns of Internet users. Online research and advocacy groups look optimistically at the (economic and social) potential of the active and technology–skilled elderly; other approaches dealing with the social appropriation of technology see obstacles and stress the dangers of an increasing digital divide between generations. Our objective is to refer to taken for granted normative assumptions of the digital div...

  6. Divided screen : the doppelgänger in German silent film

    OpenAIRE

    Rashidi, Bahareh

    2007-01-01

    The proliferation of the doppelgänger theme in so many films of Wilhemine and Weimar Germany raises the question of its historical significance, in particular during Germany’s “crisis of classical modernity”. While previous studies have addressed the double from a narrative perspective, focusing on its psychological significations as divided self, this thesis instead considers the theme from a structural and historical perspective: how, as a technical reproduction of the human ...

  7. Internet für alle? Die Diskussion des »digital divide« revisited

    OpenAIRE

    Krings, Bettina; Riehm, Ulrich

    2006-01-01

    Die Diskussion um das digital divide oder die digitale Spaltung, wie sie für den deutschsprachigen Raum übersetzt wird, wird nun schon seit nahezu zehn Jahren intensiv geführt.1 Vor allem im Rahmen der politischen Diskussion hat sich das Bedrohungsszenario einer digitalen Spaltung innerhalb der Gesellschaften festgesetzt. Aber auch weite Teile der wissenschaftlichen Debatte haben dieses Szenario aufgegriffen und aus unterschiedlichen Perspektiven beleuchtet und analysiert. Obgleich sich di...

  8. BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development

    OpenAIRE

    Reviewed by Ozlem OZAN,

    2009-01-01

    BRIDGING THE KNOWLEDGE DIVIDEEducational Technology for DevelopmentMarshall,S., Kinuthia, W. & Wallace Taylor., Ed.D.; Information Age Publishing, Charlotte, NC, SBN: 978-1-60752-109-9, p.433, 2009Reviewed by Ozlem OZANFaculty of EducationEski?ehir Osmangazi UniversityEskisehir, TURKEYThe concept of a knowledge divide is used to describe the gap in living conditions between those who can find, manage and process information or knowledge, and those who are impaired in this, for one reason or a...

  9. Nationality Divides and Shared Leadership in Multinational Team

    DEFF Research Database (Denmark)

    Paunova, Minna

    2015-01-01

    How shared leadership is enacted in teams that are nationally diverse is currently under- researched, despite the increasing presence of multinational teams in the workplace. To better understand the phenomenon of shared leadership in multinational team contexts, we propose two ways in which nationality-based characteristics of members may divide teams and affect leadership. We argue that the national belonging of members may result in both identity subgroups and status ranks. However, the confi...

  10. Calcium restriction prolongs metaphase in dividing Tradescantia stamen hair cells

    OpenAIRE

    1985-01-01

    Agents that lower extracellular calcium concentration (EGTA) or modulate calcium transport (lanthanum or D600) have been applied to dividing stamen hair cells of Tradescantia and analyzed for their ability to change the following: (a) the time required to progress from nuclear envelope breakdown to the onset of anaphase (metaphase transit time), (b) the time required to progress from anaphase to the initiation of the cell plate, and (c) the rate of chromosome motion in anaphase. Control cells...

  11. Adaptation Procedure for Multi-dividing Ontology Algorithm

    Directory of Open Access Journals (Sweden)

    Wei Gao

    2013-01-01

    Full Text Available Ontology, as a structured conceptual model of knowledge representation and storage, has widely used in computer science, biomedical and social science. Ontology algorithms even become the core algorithms in information retrieval and thus raise more and more attention. In this study, we propose the adaptation procedure for ontology algorithm in multi-dividing setting. The new technology helps to adapt an unknown parameter and we determine the generalization error bound for such adaptation procedure under certain assumption.

  12. Europeanization and Conflict Resolution: Case Studies from the Divided Periphery

    OpenAIRE

    COPPIETERS, Bruno; Huysseune, Michel; Kovziridze, Tamara; NOUTCHEVA, Gergana; Tocci, Nathalie; Emerson, Michael; VAHL, Marius

    2004-01-01

    The enlarging EU is increasingly drawn into secessionist conflicts on its southern and eastern peripheries. This book examines the relevance of European integration for conflict settlement and resolution in divided states through a comparison of four case studies: Cyprus, Serbia and Montenegro, Moldova and the Transnistrian conflict and the Georgia-Abkhaz conflict. The authors explore the historical background of each of these conflicts and examine the degree of Europeanization, the mediation...

  13. Traffic Prediction Based on SVM Training Sample Divided by Time

    OpenAIRE

    Lingli Li; Hongxia Xia; Lin Li; Qingbo Wang

    2013-01-01

    In recent years, the volume of traffic is rapidly increasing. When vehicles running through the tunnel are more intensive or move slowly, the tunnel environment occurs deteriorated sharply, which affects the normal operation of the vehicle in the tunnel. This paper uses the result of previous mining association rules to select feature items and to establish four training samples divided by time. Then the training samples are utilized to create the SVM classification model. Finally the trained...

  14. THE DIGITAL DIVIDE: ICT DEVELOPMENT INDICES IN MEXICO

    Directory of Open Access Journals (Sweden)

    Edgar TELLO-LEAL

    2012-01-01

    Full Text Available The integration of Information and Communication Technologies (ICTs to the manufacturing sector enables to reduce production, management and marketing costs, allowing achieve higher levels of competitiveness. In the social area, ICTs are tools of inclusion improving the provision of education, health and government services, as well as expanding its coverage area of these services. To achieve these benefits it is required a proper incorporation and adaptation of ICTs in the social area, as well as, the development of required ICT services, properly. In this work, we analyze the role of the digital divide in the information society, as ground for social exclusion in the use of ICT in Mexico. Afterwards, the behavior of the digital divide is analyzed, with its different dimensions through time, also describing the penetration and development levels of ICT. Moreover, the case of study of university students enrolled in Information Technology careers is discussed in order to determine the existence of a digital divide and its parameters. Finally, a diagnosis about the growth of the Internet and mobile telephony services in Mexico is carried out, considering the prevailing world economic situation.

  15. Dividing Streamline Formation Channel Confluences by Physical Modeling

    Directory of Open Access Journals (Sweden)

    Minarni Nur Trilita

    2010-02-01

    Full Text Available Confluence channels are often found in open channel network system and is the most important element. The incoming flow from the branch channel to the main cause various forms and cause vortex flow. Phenomenon can cause erosion of the side wall of the channel, the bed channel scour and sedimentation in the downstream confluence channel. To control these problems needed research into the current width of the branch channel. The incoming flow from the branch channel to the main channel flow bounded by a line distributors (dividing streamline. In this paper, the wide dividing streamline observed in the laboratory using a physical model of two open channels, a square that formed an angle of 30º. Observations were made with a variety of flow coming from each channel. The results obtained in the laboratory observation that the width of dividing streamline flow is influenced by the discharge ratio between the channel branch with the main channel. While the results of a comparison with previous studies showing that the observation in the laboratory is smaller than the results of previous research.

  16. Learnings from investigations on SG divider plates: Coupling field characterizations with numerical mechanical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Rossillon, F., E-mail: frederique.rossillon@edf.fr [EDF SEPTEN, 12-14 Avenue Dutrievoz, Villeurbanne (France); Depradeux, L. [EC2-MS, 66 Bd Niels Bohr, Villeurbanne (France); Miloudi, S. [EDF CEIDRE, CNPE de Chinon, Avoine (France); Deforge, D. [EDF CEIDRE, 2 Rue Ampère, Saint Denis (France); Lemaire, E. [EDF UNIE, Cap Ampère, Saint Denis (France); Massoud, J.P. [EDF SEPTEN, 12-14 Avenue Dutrievoz, Villeurbanne (France)

    2014-04-01

    Nickel based alloys stress corrosion cracking (SCC) has been a major concern for the nuclear power plant utilities since the 1970s. Since 2002, SCC indications have been found on steam generator (SG) divider plates made of alloy 600 on French PWRs (pressurized water reactors) 900 MWe units. Although integrity is not questioned, many studies have been conducted to deepen understanding of the phenomenon. Among numerous studies to investigate the SCC damage phenomena, advanced mechanical analysis has been performed to improve the knowledge of the in-service loadings of the SG 900 MWe partition stub and divider plate. Manufacturing steps are taken into account, such as welding and the first hydro-test, to have a more precise description of the mechanical states in the vicinity of the welds where SCC is likely to occur. Recently, EDF hot laboratories made destructive examinations of a decommissioned SG. To fulfil the analyses computations have been carried out on the dedicated configuration. A 3D FE model, including the simulation of the welding and hydro-test, has been set up. Comparisons with experimental investigations on the divider plate of decommissioned SG have shown a good agreement between experimental and numerical results. These results emphasize the redistribution of weld residual stresses after the first hydro-test, and the effect of hydro-testing on the plastic deformation of the stub only in some specific cases of 900 MWe SG.

  17. Can Water Store Charge?

    Science.gov (United States)

    Ovchinnikova, Kate; Pollack, Gerald H.

    2010-01-01

    Previous work from this and other laboratories has demonstrated large pH gradients in water. Established by passing current between immersed electrodes, pH gradients between electrodes were found to disappear slowly, persisting for tens of minutes after the current had been turned off. We find here that these pH gradients reflect a genuine separation of charge: at times well after disconnection of the power supply, current could be drawn through a resistor placed between the charging electrodes or between pairs of electrodes positioned on either side of the midline between original electrodes. In some experiments, it was possible to recover the majority of charge that had been imparted to the water. It appears, then, that water has the capacity to store and release substantial amounts of charge. PMID:19053655

  18. Wireless Technologies Bridging the Digital Divide in Education

    Directory of Open Access Journals (Sweden)

    Gerard Smyth

    2006-06-01

    Full Text Available The objective of this paper is to demonstrate how the latest wireless standards and technologies may overcome the digital divide in education in the developed and developing worlds. The concept of the digital divide is discussed in the traditional socio-economic sense and expanded in terms of the learner's location, age, culture and background. It is important that we understand the full extent and complexities of this division if we are to effectively bridge it. Why and how the digital divide may be bridged is examined. Apart from the inherent inequalities that need to be addressed from an ethical perspective, it is very much in the interests of governments and citizens globally that Information and Communications Technology (ICT is made available to all as quickly and cost-effectively as possible. New forms of wireless protocols are overcoming challenges of terrain, infrastructure and finance. It is proposed that, by leveraging open broadband wireless standards, like Wireless Fidelity (Wi-Fi* and Worldwide Interoperability for Microwave Access (WiMAX*, and implementing Mobile Computing architecture, it is now possible to make dramatic strides in this direction. The paper continues with a general overview of these wireless standards and technologies followed by an in-depth look at Wi-Fi and WiMAX. The paper goes on to give examples of the Innovation Centre's involvement in delivering solutions and new usage models for eLearning that utilize the latest wireless standards and technologies. The challenges and successes of these projects are outlined and metrics are presented where available.

  19. Informaticiens Sans Frontières. Helping to bridge the Digital Divide

    CERN Document Server

    Josiane Uwantege

    2009-01-01

    SF was formed as a CERN club during the World Summit for the Information Society, in Geneva, in 2003. Today we are involved in a number of international projects aimed to helping Africa bridge the Digital Divide, as well as using computing power (BOINCs) in the research against Malaria, or creating GRIDs that could allow African universities to join us in scientific research projects such as the LHC. Our latest project, named MANGO Net, is aimed at capacity building, by creating a network of computer assembly schools across the continent, which would form hardware and software technicians, create assembly centres, and lay the foundation for a future IT industry.

  20. Affinity and Hostility in Divided Communities: a Mathematical Model

    CERN Document Server

    Thron, Christopher

    2015-01-01

    We propose, develop, and analyze a mathematical model of intergroup attitudes in a community that is divided between two distinct social groups (which may be distinguished by religion, ethnicity, or some other socially distinguishing factor). The model is based on very simple premises that are both intuitive and justified by sociological research. We investigate the behavior of the model in various special cases, for various model configurations. We discuss the stability of the model, and the continuous or discontinuous dependence of model behavior on various parameters. Finally, we discuss possible implications for strategies to improve intergroup affinity, and to defuse tension and prevent deterioration of intergroup relationships.

  1. Young Cool Stars Divided on the Issue of Rotation

    OpenAIRE

    Meibom, Søren

    2008-01-01

    We present the results of a combination of new stellar rotation periods and extensive information about membership in the young open clusters M35 and M34. The observations show that late-type members of both clusters divide into two distinct groups, each with a different dependence of rotation on mass (color). We discuss these new results in the context of existing rotation data for cool stars in older clusters, with a focus on the dependence of rotation on mass and age. We ...

  2. Divide by 4 the emissions: the Negatep scenario

    International Nuclear Information System (INIS)

    The Negatep scenario is proposed in the framework of the french energy policy, aiming to divide by 4 the CO2 emissions for 2050. After an evaluation of the today situation concerning the energy consumption and needs, the scenario proposes some ways of energy conservation in different sectors, other energy sources in place of the fossil fuels, the energy needs by sectors. The last part of the document provides the main consumption posts, the CO2 releases and the approach. (A.L.B.)

  3. Traffic Prediction Based on SVM Training Sample Divided by Time

    Directory of Open Access Journals (Sweden)

    Lingli Li

    2013-07-01

    Full Text Available In recent years, the volume of traffic is rapidly increasing. When vehicles running through the tunnel are more intensive or move slowly, the tunnel environment occurs deteriorated sharply, which affects the normal operation of the vehicle in the tunnel. This paper uses the result of previous mining association rules to select feature items and to establish four training samples divided by time. Then the training samples are utilized to create the SVM classification model. Finally the trained SVM model is used to prediction the tunnel traffic situation. Through traffic situation prediction, effective decisions can be made before traffic jams, and ensure that the tunnel traffic is normal.  

  4. On a nonlinear Kalman filter with simplified divided difference approximation

    KAUST Repository

    Luo, Xiaodong

    2012-03-01

    We present a new ensemble-based approach that handles nonlinearity based on a simplified divided difference approximation through Stirling\\'s interpolation formula, which is hence called the simplified divided difference filter (sDDF). The sDDF uses Stirling\\'s interpolation formula to evaluate the statistics of the background ensemble during the prediction step, while at the filtering step the sDDF employs the formulae in an ensemble square root filter (EnSRF) to update the background to the analysis. In this sense, the sDDF is a hybrid of Stirling\\'s interpolation formula and the EnSRF method, while the computational cost of the sDDF is less than that of the EnSRF. Numerical comparison between the sDDF and the EnSRF, with the ensemble transform Kalman filter (ETKF) as the representative, is conducted. The experiment results suggest that the sDDF outperforms the ETKF with a relatively large ensemble size, and thus is a good candidate for data assimilation in systems with moderate dimensions. © 2011 Elsevier B.V. All rights reserved.

  5. Quantum Cyclic Code of length dividing $p^{t}+1$

    CERN Document Server

    Dutta, Sagarmoy

    2010-01-01

    In this paper, we study linear cyclic stabiliser codes of length dividing $p^t+1$, for a positive integer $t$. We prove that if $t$ is odd, no such codes exists and give a complete characterisation when $t$ is even. Our characterisation of these codes directly gives us explicit constructions which includes the well studied Laflamme code. Furthermore, we also show that any linear cyclic stabiliser code over $\\mathbb{F}_p$ whose length divides $p^{2m}+1$ can never be a CSS code unless it has distance $1$ and hence trivial. The characterisation of these codes also gives us efficient decoding algorithms. More precisely, we can extend the notion of BCH distance of classical cyclic codes to these codes and correct errors within the BCH limit. In order to construct these codes, we start from a general notion of cyclicity for quantum code. This can be of independent interest as our notion of cyclicity is applicable to non-stabiliser codes as well.

  6. Chirped and divided-pulse Sagnac fiber amplifier

    Science.gov (United States)

    Guichard, Florent; Zaouter, Yoann; Hanna, Marc; Mai, Khanh-Lin; Morin, Franck; Hönninger, Clemens; Mottay, Eric; Georges, Patrick

    2015-03-01

    Femtosecond fiber chirped pulse amplifiers have numerous advantages, but are limited in energy because of the small interaction area with the fiber core. In this contribution, we create two orthogonally-polarized stretched pulse replicas in the time domain, following the divided-pulse amplification (DPA) principle. This beam is subsequently separated into two counter-propagating beams in a Sagnac interferometer to finally generate four pulse replicas. These pulses are amplified in two state-of-the-art large mode area rod-type fiber amplifiers in series, before final coherent combination and compression. Because the stretched-pulse duration is of the order of hundreds of picoseconds, the DPA delay is induced using a freespace interferometer with reasonable arm lengths of few tens of centimeters. The use of a common interferometer to divide and recombine temporal pulse replicas, together with the Sagnac geometry, results in an identical optical path for all four replicas. Therefore, the whole spatio-temporal combining architecture is passive, avoiding the need for active electronic stabilization systems. Because we only use two temporal replicas, the system is immune to differential saturation levels or B-integrals between successive pulses: this is compensated by controlling the amplitude of both pulses at the input of the amplifying setup. This setup allows the generation of 1 mJ, 300 fs compressed pulses at 50 kHz repetition rate, corresponding to 50 W output average power, with a combining efficiency above 90% at all power levels.

  7. Attitude estimation by divided difference filter in quaternion space

    Science.gov (United States)

    Ahmadi, Mohammad; Khayatian, Alireza; Karimaghaee, Paknoush

    2012-06-01

    This article considers the application of Divided Difference Filter (DDF) to the orientation estimation, based on a quaternion-error continuous-discrete time model. DDF is a nonlinear estimator that in contrast to Taylor's expansion of extended Kalman Filter (EKF), exploit the polynomial approximations as a multivariable extension of Stirling's interpolation formula and require no derivatives. The DDF can be based on 1st and 2nd order Stirling's interpolation, which is named the divided difference filter-1st order (DDF1) and the divided difference filter-2nd order (DDF2). The orientation kinematics is defined in a quaternion vector space that unlike the Euler angle representation does not have any singularity problem. The presented nonlinear orientation model is an exact error model and is independent of the rigid body dynamics. The nonlinear process model includes six error-states in which only non-scalar elements of quaternion error vector are included in the error-state equations. The fourth element of quaternion error vector, which obeys unit norm constraint, is removed from system states to alleviate the estimated error covariance matrix divergence. The measurement system is a MARG sensor, which consists of a tri-axial rate gyro, a tri-axial accelerometer and a tri-axial magnetometer. The nonlinear measurement model is obtained based on the principals of magnetometer and accelerometer and the properties of the quaternion vector space. For the presented nonlinear orientation model, the performance of three filters namely DDF, EKF and Unscented Kalman Filter (UKF) is compared for different sampling frequencies in terms of the rms error, the captured area under the error norm curve, the estimated state variance and the computational cost. It is shown that under the same initial angle-error conditions, DDFs and UKF are more robust than EKF. The DDFs perform better than unscented Kalman filter (UKF) although the computational load for UKF is less. Among DDF1 and DDF2, DDF2's performance is slightly better but with more computation load. In the case of no initial angle-error conditions, the performance of the four filters is the same especially when the low noise level condition is considered.

  8. Digital Divide between Teachers and Students in Urban Bangladesh

    DEFF Research Database (Denmark)

    Khalid, Md. Saifuddin

    2011-01-01

    Telecom boom since 2000 and ‘Digital Bangladesh’ campaign since late 2008 created significant nationwide hype, resulting rapid increase in the use of digital devices. While studies are being conducted to use the ability of “power users of technology” for reducing digital divide, there is hardly any data available on them in Bangladesh context. A study was conducted to study the digital divide and ICT usage pattern among the urban students and teachers of schools and colleges in Dhaka, the capital of Bangladesh. About 75 students enrolled in probability and statistics course of Independent University, Bangladesh (IUB) in autumn 2009 participated in conducting survey activities. Total 33 academic institutes were south for approval and 11 could be surveyed before the Christmas and annual recess. Responses from 6 other academics institutes were collected from the personal networks of students. A questionnaire was developed based on initial semi-structured interview with randomly selected students from these academic institutions. The 41-question questionnaire was developed to study the usage of computer, internet, mobile and other handheld devices, radio, television and CD/DVD players. A slightly different questionnaire was developed for teachers. 965 students and 185 teachers participated in the survey. Among student respondents 37% were from English Medium and 63% from Bangla medium institutions. From class VI –XII, the survey group represent the secondary and higher secondary education level in Bangladesh. Male respondents were 53% and female 43%, remaining are missing. Responses collected using paper-based questionnaires were put on a learning management system’s (LMS) questionnaire survey module. Irrespective of type of ICT device higher percentage of English medium students ‘own’ and know ‘how to use’ compared to Bangla medium students. Significantly higher percentage of students can use and own desktop, laptop, cellphone, iPOD and MP3 player. While teachers mostly use computers for work (73%), study (45%) and listening music (34%), students use for playing games (63%), listening musing (62%) and study (44%). 69% teachers and 66% students use social networking sites. Top three online activities for students are music (53%), games (47%) and chat (42%), for teachers these are study (55%), chat (40%) and music (33%). Students use more mobile features than teachers. Interestingly 59% teachers and 61% students have more than one SIM card. More than 50% of students and teachers use mobile for listening radio. 55% or more teachers and 67% or more students ‘own’ a desktop. 90% or more teachers and 74% or more students ‘know how to use’ desktop computer. Further study is required to gain insight into digital divide and associated reasons in four different educations systems in Bangladesh.

  9. Divided-pulse nonlinear amplification and simultaneous compression

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiang; Zhang, Qingshan; Sun, Tingting; Chen, Jie; Wang, Yuqing; Guo, Zhengru; Yang, Kangwen [Shanghai Key Laboratory of Modern Optical System, and Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Guo, Zhanhua [Shanghai Langyan Optoelectronic Science and Technology Co., LTD, Shanghai 200433 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, and Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

    2015-03-09

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560?nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780?nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.

  10. Universal Service in a Broader Perspective: The European Digital Divide

    Directory of Open Access Journals (Sweden)

    Maria Concepcion GARCIA-JIMENEZ

    2009-01-01

    Full Text Available Ensuring universal service is a top objective in many countries in order that all the citizens can have access basic communications services. Although the ICT equipment in households and its usage by individuals are essential prerequisites for benefiting from ICTs, the situation in the European Union is far from uniform. This article provides a description of the European information society development scenario using the values reached by the member states in a set of indicators selected for measuring said progress in households. Two tools are used for providing a broader perspective of the digital divide: a composite index and the cluster analysis. Below, a study is provided on what variables are relevant for interpreting the situation that is presented.

  11. Bifurcation in asymmetric plasma divided by a magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Ohi, K.; Naitou, H.; Tauchi, Y.; Fukumasa, O. [Department of Electrical and Electronic Engineering, Yamaguchi Univ., Ube, Yamaguchi (Japan)

    2001-05-01

    A magnetic filter (MF) reflecting electrons from both sides can separate a low-temperature and low-density subplasma from a high-temperature and high-density main plasma. The one-dimensional numerical simulation by the particle-in-cell code revealed that, depending on the asymmetry, the plasma divided by the MF behaves dynamically or statically [K. Ohi et al., Physics of Plasmas 8, 23 (2001)]. The transition between the two bifurcated states is discontinuous. In the dynamic state, the autonomous potential oscillation in the subplasma is synchronized with the passage of the shock wave structure generated by the modulated ion beam from the main plasma. The stationary phase of the dynamic state appears after the amplitude of the potential oscillation in the subplasma grows exponentially from the thermal noise. In the static state, the system is stable to the growth of the potential oscillation in the subplasma. (author)

  12. Flagellation of Pseudomonas aeruginosa in newly divided cells

    Science.gov (United States)

    Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

    2015-03-01

    For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

  13. Bayesian Blocks Divide and Conquer, MCMC, and Cell Coalescence Approaches

    CERN Document Server

    Scargle, J D

    2000-01-01

    Identification of local structure in intensive data -- such as time series, images, and higher dimensional processes -- is an important problem in astronomy. Since the data are typically generated by an inhomogeneous Poisson process, an appropriate model is one that partitions the data space into cells, each of which is described by a homogeneous (constant event rate) Poisson process. It is key that the sizes and locations of the cells are determined by the data, and are not predefined or even constrained to be evenly spaced. For one-dimensional time series, the method amounts to Bayesian changepoint detection. Three approaches to solving the multiple changepoint problem are sketched, based on: (1) divide and conquer with single changepoints, (2) maximum posterior for the number of changepoints, and (3) cell coalescence. The last method starts from the Voronoi tessellation of the data, and thus should easily generalize to spaces of higher dimension.

  14. Complex behavior in asymmetric plasma divided by a magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Ohi, Kazuo; Naitou, Hiroshi; Tauchi, Yasushi; Fukumasa, Osamu [Yamaguchi Univ., Dept. of Electrical and Electronic Engineering, Ube, Yamaguchi (Japan); Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2001-07-01

    A bifurcation from the static state to the dynamic state in the asymmetric plasma divided by the magnetic filter (MF) is studied by an one-dimensional particles simulation. A low temperature and low density subplasma is in contact with a high temperature and high density main plasma at the MF. In the dynamic state, autonomous oscillation of the electrostatic potential in the subplasma is observed along with the transit of the shock wave structure [K. Ohi, H. Naitou, Y. Tauchi, and O. Fukumasa, Phys. Plasmas 8, 23 (2001)]. By changing the control parameter of B{sub 0} very slowly, the existence of the hysteresis in the relation of {delta}{phi}{sub s} versus B{sub 0} is verified. Here B{sub 0} is the strength of the magnetic field at the center of the MF and {delta}{phi}{sub s} is twice the amplitude of the self-sustained potential oscillation in the subplasma. (author)

  15. Divided-pulse nonlinear amplification and simultaneous compression

    International Nuclear Information System (INIS)

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560?nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780?nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature

  16. Nationality Divides and Shared Leadership in Multinational Team

    DEFF Research Database (Denmark)

    Paunova, Minna

    How shared leadership is enacted in teams that are nationally diverse is currently under- researched, despite the increasing presence of multinational teams in the workplace. To better understand the phenomenon of shared leadership in multinational team contexts, we propose two ways in which nationality-based characteristics of members may divide teams and affect leadership. We argue that the national belonging of members may result in both identity subgroups and status ranks. However, the configurational properties of identity subgroups and status ranks will have distinct effects on team dynamics, shared leadership within the team, and team performance. We conduct two empirical studies, and find that the number and balance of identity subgroups have important implications for multinational team functioning, in line with social identity approaches. Interestingly, the number and balance of status ranks also affects shared leadership, but not as hypothesized.

  17. Effect of branch spacing on losses for dividing flow

    Energy Technology Data Exchange (ETDEWEB)

    Hecker, G.E.; Nystrom, J.B.; Qureshi, N.A.

    1977-03-01

    Since few data are available regarding the effect of branch spacing on discharge and energy loss coefficients for dividing flow, tests were conducted for a line manifold using three branches. A branch geometry typical of an actual diffuser design was used, and the branch to main pipe diameter ratio and the relative spacing between branches was varied by increments. The variation in discharge coefficient is presented as a function of the ratio of velocity head to total head, whereas loss coefficients are plotted versus relative velocity. A family of curves for each diameter ratio shows the effect of relative branch spacing. Test data indicated that the branch discharge coefficient increased and branch losses decreased with a decrease in spacing due to the change in velocity profile in the main pipe. However, the loss coefficient for flow past the branch in the main pipe increased with a decrease in spacing.

  18. How Visibility and Divided Attention Constrain Social Contagion

    CERN Document Server

    Hodas, Nathan Oken

    2012-01-01

    How far and how fast does information spread in social media? Researchers have recently examined a number of factors that affect information diffusion in online social networks, including: the novelty of information, users' activity levels, who they pay attention to, and how they respond to friends' recommendations. Using URLs as markers of information, we carry out a detailed study of retweeting, the primary mechanism by which information spreads on the Twitter follower graph. Our empirical study examines how users respond to an incoming stimulus, i.e., a tweet (message) from a friend, and reveals that %retweeting behavior is constrained by a few simple principles. the "principle of least effort" combined with limited attention plays a dominant role in retweeting behavior. Specifically, we observe that users retweet information when it is most visible, such as when it near the top of their Twitter stream. Moreover, our measurements quantify how a user's limited attention is divided among incoming tweets, pro...

  19. Spike sorting for polytrodes: a divide and conquer approach

    Directory of Open Access Journals (Sweden)

    Nicholas V. Swindale

    2014-02-01

    Full Text Available In order to determine patterns of neural activity, spike signals recorded by extracellular electrodes have to be clustered (sorted with the aim of ensuring that each cluster represents all the spikes generated by an individual neuron. Many methods for spike sorting have been proposed but few are easily applicable to recordings from polytrodes which may have 16 or more recording sites. As with tetrodes, these are spaced sufficiently closely that signals from single neurons will usually be recorded on several adjacent sites. Although this offers a better chance of distinguishing neurons with similarly shaped spikes, sorting is difficult in such cases because of the high dimensionality of the space in which the signals must be classified. This report details a method for spike sorting based on a divide and conquer approach. Clusters are initially formed by assigning each event to the channel on which it is largest. Each channel-based cluster is then sub-divided into as many distinct clusters as possible. These are then recombined on the basis of pairwise tests into a final set of clusters. Pairwise tests are also performed to establish how distinct each cluster is from the others. A modified gradient ascent clustering (GAC algorithm is used to do the clustering. The method can sort spikes with minimal user input in times comparable to real time for recordings lasting up to 45 minutes. Our results illustrate some of the difficulties inherent in spike sorting, including changes in spike shape over time. We show that some physiologically distinct units may have very similar spike shapes. We show that RMS measures of spike shape similarity are not sensitive enough to discriminate clusters that can otherwise be separated by principal components analysis. Hence spike sorting based on least-squares matching to templates may be unreliable. Our methods should be applicable to tetrodes and scaleable to larger multi-electrode arrays (MEAs.

  20. BRIDGING THE KNOWLEDGE DIVIDE Educational Technology for Development

    Directory of Open Access Journals (Sweden)

    Reviewed by Ozlem OZAN,

    2009-10-01

    Full Text Available BRIDGING THE KNOWLEDGE DIVIDEEducational Technology for DevelopmentMarshall,S., Kinuthia, W. & Wallace Taylor., Ed.D.; Information Age Publishing, Charlotte, NC, SBN: 978-1-60752-109-9, p.433, 2009Reviewed by Ozlem OZANFaculty of EducationEski?ehir Osmangazi UniversityEskisehir, TURKEYThe concept of a knowledge divide is used to describe the gap in living conditions between those who can find, manage and process information or knowledge, and those who are impaired in this, for one reason or another. In the 21st century, the emergence of the knowledge society becomes pervasive hence the information and ICT systems that support knowledge are very important.This book discusses how educational technology can be used to transform education and assist developing communities to close the knowledge divide. Its broader audience is anyone who is interested in educational technology for development. In the book you can find best practices and case studies especially from countries in Africa.The book is edited by Stewart Marshall, Wanjira Kinuthia, Wallace Taylor. Professor Stewart Marshall, PhD, is the director of the Academic Division of the University of the West Indies Open Campus (UWIOC and holds the UNESCO Chair in Educational Technologies.Dr. Wanjira Kinuthia is assistant professor of Learning Technologies at Georgia State University. She works as an instructional designer in higher education and business and industry for several years. Professor Wallace Taylor, PhD, is a founding director of The Information Society Institute (TISI, a non-profit academic, research, and policy development organization based in South Africa.The book is consisted of 433 pages (+xxxv covering 24 articles divided into four sections and provides information about flexible learning for empowerment, managing and communicating knowledge, flexible delivery in higher education and preparing teacher using flexible approaches.Topics covered in the book are as follows:Flexible Education and Community Development, Flexible Learning for Community Economic Development, Contribution of the IDE in Promoting Gender Equality and in Empowering Women in Swaziland, A Virtual Wheel of Fortune?: Enablers and Constraints of ICTs in Higher Education in South Africa, Delivering Distance Education for the Civil Service in the UK: The University of Chester’s Foundation for Government Program, Knowledge Management Strategies for Distance Education, The Effectiveness of Mobile Short Messaging Service (SMS Technologies in the Support of Selected Distance Education Students of Makerere University, Uganda, The Impact of Video Conferencing on Distance Education Courses: A University of Namibia Case Study, Open Resources for Open Learning in Developing Countries: Deciphering Trends for Policies, Quality, and Standards Considerations, Freedom, Innovation, and Equity with Open Source Software, Copyright Issues and their Impact on Flexible Education in Africa, University Education for National Development: Makerere University’s Dual Mode Experience, Considerations for Higher Education Distance Education Policy for Development: A Case of the University of Botswana,Blended Online and Face-to-Face Learning: A Pilot Project in the Faculty of Education, Eduardo Mondlane University, Evaluating the Impact of CABLE: A Cognitive Apprenticeship-Based Learning Environment, From Distance Learning to E-learning in Central and Northern Mozambique, A Framework for the Delivery of Cross-Regional Distance Education to Professionals in Developing Countries, Distance Learning—Challenges and Opportunities for Postgraduate Medical Education: A Case Study of Postgraduate Training in Family Medicine Using Distance Learning at the University of the West Indies (2001–2006, Pre-service Teacher Preparation and Effective eLearning, Distance Teacher Training in Rwanda: Comparing the Costs, Beckoning E-Learners through Exploration of Computer Technology, Educational Technology and Flexible Education in Nigeria: Meeting the Need for Effective Teacher Education, Fostering Digital Liter

  1. Divided attention during retrieval suppresses false recognition in confabulation.

    Science.gov (United States)

    Ciaramelli, Elisa; Ghetti, Simona; Borsotti, Marco

    2009-02-01

    The present research tested the hypothesis that false recognition in confabulating patients results, at least in part, from sustained processing of irrelevant information about test items. Thus, we predicted that false recognition would be reduced if cognitive resources available for such a processing are experimentally reduced. Two experiments provided evidence consistent with this proposal. In Experiment 1, confabulating patients exhibited lower false recognition in a divided attention (DA) compared to a full attention (FA) retrieval condition. The opposite trend was observed in non-confabulating patients with comparable memory and executive deficits and normal controls. In Experiment 2, in a Deese-Roediger-McDermott paradigm, confabulating patients exhibited lower false recognition to lures that were unrelated to the studied words in the DA compared to the FA retrieval condition, but unvaried levels of false recognition to critical lures. In contrast, false recognition to both unrelated and critical lures increased in non-confabulating patients and normal controls in the DA compared to the FA condition. These results are consistent with the hypothesis that an excessive processing of task-irrelevant memories at retrieval may contribute to false recognition in confabulating patients. PMID:19150516

  2. Informaticiens Sans Frontieres: Helping to bridge the Digital Divide

    CERN Document Server

    CERN. Geneva

    2009-01-01

    ISF was formed as a CERN club during the World Summit for the Information Society, in Geneva, in 2003. Today we are involved in a number of international projects aimed to helping Africa bridge the Digital Divide, as well as using computing power (BOINCs) in the research against Malaria, or creating GRIDs that could allow African universities to join us in scientific research projects such as the LHC. Our latest project, named MANGO Net, is aimed at capacity building, by creating a network of computer assembly schools across the continent, which would form hardware and software technicians, create assembly centres, and lay the foundation for a future IT industry. ISF est né comme un club du CERN, en 2003, pendant le Sommet Mondiale de la Société de l'information à Genève. Aujourd'hui nous participons à plusieurs projets avec le but d'aider l'Afrique à reduire la Fracture Numérique, ou de fournir de la puissance de calcul (BOINC) à la recherche contre le Paludisme, ou en créant des GRIDs qui pourra...

  3. Application System Architecture for Cellular Phones by Dividing Interaction Logics

    Science.gov (United States)

    Kitamura, Misayo; Todoroki, Nobutoshi; Akiyoshi, Masanori; Kojima, Taizo

    This paper describes application system architecture using cellular phones as user interface devices, which enables users to interact with the system by graphic symbols on a client screen. Our approach has the following features: (i) divided interaction logics running on a server and a Java phone client; both interaction logics cooperate to accomplish a user's operation using a simplified script, (ii) local interaction which enables users to handle figures on a client screen without connecting to a server, and (iii) device-independent script which hides the differences of API sets among various cellular phones. By using this architecture, complicated figures including lots of graphic symbols can be displayed in spite of program-size limitation on a client device, and application programs including same interaction logics are just described once for various cellular phones. Our experiments show the advantage of the local interaction. A client program can respond immediately when handling complicated figures. The ratio of requests to the server is reduced to 23%. It takes less than 9 seconds to display typical contents, which is good enough for practical use. This method also reduces development costs at the second development or later.

  4. Thalamic control of sensory selection in divided attention.

    Science.gov (United States)

    Wimmer, Ralf D; Schmitt, L Ian; Davidson, Thomas J; Nakajima, Miho; Deisseroth, Karl; Halassa, Michael M

    2015-10-29

    How the brain selects appropriate sensory inputs and suppresses distractors is unknown. Given the well-established role of the prefrontal cortex (PFC) in executive function, its interactions with sensory cortical areas during attention have been hypothesized to control sensory selection. To test this idea and, more generally, dissect the circuits underlying sensory selection, we developed a cross-modal divided-attention task in mice that allowed genetic access to this cognitive process. By optogenetically perturbing PFC function in a temporally precise window, the ability of mice to select appropriately between conflicting visual and auditory stimuli was diminished. Equivalent sensory thalamocortical manipulations showed that behaviour was causally dependent on PFC interactions with the sensory thalamus, not sensory cortex. Consistent with this notion, we found neurons of the visual thalamic reticular nucleus (visTRN) to exhibit PFC-dependent changes in firing rate predictive of the modality selected. visTRN activity was causal to performance as confirmed by bidirectional optogenetic manipulations of this subnetwork. Using a combination of electrophysiology and intracellular chloride photometry, we demonstrated that visTRN dynamically controls visual thalamic gain through feedforward inhibition. Our experiments introduce a new subcortical model of sensory selection, in which the PFC biases thalamic reticular subnetworks to control thalamic sensory gain, selecting appropriate inputs for further processing. PMID:26503050

  5. The Digital Divide in Romania – A Statistical Analysis

    Directory of Open Access Journals (Sweden)

    Daniela BORISOV

    2012-06-01

    Full Text Available The digital divide is a subject of major importance in the current economic circumstances in which Information and Communication Technologies (ICT are seen as a significant determinant of increasing the domestic competitiveness and contribute to better life quality. Latest international reports regarding various aspects of ICT usage in modern society reveal a decrease of overall digital disparity towards the average trends of the worldwide ITC’s sector – this relates to latest advances of mobile and computer penetration rates, both for personal use and for households/ business. In Romania, the low starting point in the development of economy and society in the ICT direction was, in some extent, compensated by the rapid annual growth of the last decade. Even with these dynamic developments, the statistical data still indicate poor positions in European Union hierarchy; in this respect, the prospects of a rapid recovery of the low performance of the Romanian ICT endowment and usage and the issue continue to be regarded as a challenge for progress in economic and societal terms. The paper presents several methods for assessing the current state of ICT related aspects in terms of Internet usage based on the latest data provided by international databases. The current position of Romanian economy is judged according to several economy using statistical methods based on variability measurements: the descriptive statistics indicators, static measures of disparities and distance metrics.

  6. Multidimensional Divide-and-Conquer and Weighted Digital Sums

    CERN Document Server

    Cheung, Y K; Golin, Mordecai; Lee, C Y James

    2010-01-01

    This paper studies three types of functions arising separately in the analysis of algorithms that we analyze exactly using similar Mellin transform techniques. The first is the solution to a Multidimensional Divide-and-Conquer (MDC) recurrence that arises when solving problems on points in $d$-dimensional space. The second involves weighted digital sums. Write $n$ in its binary representation $n=(b_i b_{i-1}... b_1 b_0)_2$ and set $S_M(n) = \\sum_{t=0}^i t^{\\bar{M}} b_t 2^t$. We analyze the average $TS_M(n) = \\frac{1}{n}\\sum_{j i_2 > ... > i_k\\geq 0$ and set $W_M(n) = \\sum_{t=1}^k t^M 2^{i_t}$. We analyze the average $TW_M(n) = \\frac{1}{n}\\sum_{j

  7. Crossing the Digital Divide: Connecting GIS, Time Series and Space-Time Arrays (Invited)

    Science.gov (United States)

    Maidment, D. R.; Salas, F.; Domenico, B.; Nativi, S.

    2010-12-01

    Hydrologic information science requires several different kinds of information: GIS coverages of water features of the land surface and subsurface; time series of observations of streamflow, water quality, groundwater levels and climate; and space-time arrays of weather, climate and remotely sensed information. Increasingly, such information is being published as web services, in standardized data structures that transmit smoothly through the internet. A large "Digital Divide" exists between the world of discrete spatial objects in GIS and associated time series, and the world of continuous space-time arrays as is used weather and climate science. In order to cross this divide, it should be possible to search for quantities such as “precipitation” and to find the information no matter whether it comprises time series of precipitation at gage sites, or space-time arrays of precipitation from Nexrad radar rainfall measurements. This means that servers of discrete space-time hydrologic data, such as the CUAHSI HydroServer, and servers of continuous space-time weather and climate data, such as the Unidata THREDDS server, should be able to be indexed in a unified manner that will permit discovery of common information types across different classes of information services. This paper will explore options for accomplishing this goal using the CUAHSI HydroServer and the Unidata THREDDS server as representative examples of information service providers. Among the options to be explored is GI-cat, a federated, standards-based catalog service developed at the Earth and Space Science Informatics Laboratory of the University of Florence.

  8. A Divide-and-Conquer Approach to Commercial Territory Design / Procedimiento divide y vencerás para el diseño de territorios comerciales

    Scientific Electronic Library Online (English)

    M. Angélica, Salazar-Aguilar; J. Luis, González-Velarde; Roger Z., Ríos-Mercado.

    2012-09-01

    Full Text Available En este trabajo se presenta un procedimiento heurístico para el diseño de territorios comerciales. El procedimiento propuesto, basado en el paradigma dividir-y-vencer, consiste básicamente en un proceso de dicotomías sucesivas a partir de una instancia dada. Durante este proceso se resuelven una ser [...] ie de subproblemas de programación cuadrática entera. Los resultados computacionales muestran que la heurística propuesta es una técnica de solución atractiva que permite la obtención de soluciones óptimas locales para instancias grandes del problema, las cuales resultan intratables al intentar resolverlas a través de métodos exactos. Abstract in english A new heuristic procedure for a commercial territory design problem is introduced in this work. The proposed procedure is based on the divide-and-conquer paradigm and basically consists of a successive dichotomy process on a given large instance of the problem. During this process, a series of integ [...] er quadratic subproblems is solved. The obtained computational results have shown that the proposed heuristic is an attractive technique for obtaining locally optimal solutions for large instances which are intractable by using exact optimization methods.

  9. Development of a new lower hybrid antenna module using a poloidal power divider

    International Nuclear Information System (INIS)

    A realistic antenna module using a poloidal divider for lower hybrid current drive (LHCD) experiment, is modelled and fabricated. In this antenna module test II, three types of poloidal dividers, which split the power in 3, are tested. (author)

  10. Research on Dividing Modeling of Female Suits Based on Cognitive Psychology

    OpenAIRE

    Gu Pin-Ying; Chen Ting; Gu Bin-Fei; Liu Guo-Lian

    2013-01-01

    According to apparel modeling aesthetics of consumers, in this paper, the detail modeling dividing lines of female suits were selected as subject. And with the evaluating indexes defined, the dividing modeling was classified and the control points of dividing lines were found. Then 90 images of women suits with different dividing modeling were drawn. And the experimental data of 64 students aged from 19 to 26 years old from Soochow University were collected by software named E-prime. At last,...

  11. The transatlantic divide over brain death determination and the debate.

    Science.gov (United States)

    Wijdicks, Eelco F M

    2012-04-01

    In 1976, the Royal College of Physicians published neurological criteria of death. The memorandum stated that-after preconditions and exclusion criteria were met-the absence of brainstem function, including apnoea testing, would suffice. In the USA, many experts felt that brain death could be only determined by demonstrating death of the entire brain. In the history of further refinement of UK and USA brain death criteria, one particular period stands out that would bring about an apparent transatlantic divide. On 13 October 1980, the British Broadcasting Corporation aired a programme entitled 'Transplants: Are the Donors Really Dead?' Several United States experts not only disagreed with the United Kingdom criteria, but claimed that patients diagnosed with brain death using United Kingdom criteria could recover. The fallout of this television programme was substantial, as indicated by a media frenzy and a 6-month period of heated correspondence within The Lancet and The British Medical Journal. Members of the Parliament questioned the potential long-term effect on the public's trust in organ transplantation. Given the concerns raised, the British Broadcasting Corporation commissioned a second programme, which was broadcast on 19 February 1981 entitled 'A Question of Life or Death: The Brain Death Debate.' Two panels debated the issues on the accuracy of the electroencephalogram and its place, the absolute need for assessing preconditions before an examination, the problems with recognition of toxins and the feasibility of doing a new prospective study in the United Kingdom, which would follow patients' examination assessed with United Kingdom criteria until cardiac standstill. The positions of the United States and United Kingdom remained diametrically opposed to each other. This article revisits this landmark moment and places it in a wider historical context. In the USA, the focus was not on the brainstem, and the definition of brain death became rapidly infused with terms such as whole brain death (all intracranial structures above the foramen magnum), cerebral death (all supratentorial structures) or higher brain death (cortical structures) virtually synonymous with persistent vegetative state. This review also identifies the fortitude of neurosurgeon Bryan Jennett and neurologist Christopher Pallis by introducing new corroborative data on the diagnosis of brain death and clarifying the United Kingdom position. Both understood that brainstem death was the infratentorial consequence of a supratentorial catastrophe. With the 1995 American Academy of Neurology practice parameters, the differences between the UK and USA brain death determination would become much less apparent. PMID:22197975

  12. A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations

    Science.gov (United States)

    Shimojo, Fuyuki; Hattori, Shinnosuke; Kalia, Rajiv K.; Kunaseth, Manaschai; Mou, Weiwei; Nakano, Aiichiro; Nomura, Ken-ichi; Ohmura, Satoshi; Rajak, Pankaj; Shimamura, Kohei; Vashishta, Priya

    2014-05-01

    We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786 432 cores for a 50.3 × 106-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16 661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques are employed for efficiently calculating the long-range exact exchange correction and excited-state forces. The NAQMD trajectories are analyzed to extract the rates of various excitonic processes, which are then used in KMC simulation to study the dynamics of the global exciton flow network. This has allowed the study of large-scale photoexcitation dynamics in 6400-atom amorphous molecular solid, reaching the experimental time scales.

  13. A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations

    International Nuclear Information System (INIS)

    We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786?432 cores for a 50.3 × 106-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16?661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques are employed for efficiently calculating the long-range exact exchange correction and excited-state forces. The NAQMD trajectories are analyzed to extract the rates of various excitonic processes, which are then used in KMC simulation to study the dynamics of the global exciton flow network. This has allowed the study of large-scale photoexcitation dynamics in 6400-atom amorphous molecular solid, reaching the experimental time scales

  14. Comparability of the black-white divide in the American speech community and the coloured-white divide in the Afrikaans speech community

    OpenAIRE

    Stell, Gerald

    2012-01-01

    This article attempts to place the discussion on the relationship between African American and European American vernacular Englishes within a broader context involving another speech community split along ethnic lines, namely South Africa’s Afrikaans speakers. It specifically attempts to compare observations on the coloured-white linguistic divide within South Africa’s Afrikaans speech community with those made on the black-white linguistic divide in the United States, with th...

  15. Digital divide and digital opportunity: Comparison, analysis and strategies for sustainable development in developing nations

    International Nuclear Information System (INIS)

    The world is witnessing a new digital economic order which may be quantified by the diffusion of information technology and globalization process. The current information technology gap (digital divide) between developed countries and developing countries is huge. Improvements in information technology (measured by the digital opportunity index) usually open up an opportunity for national/regional growth and development. There is a need for scientific investigation on the digital divide, digital opportunity index and their consequences. This paper presents a critical analysis of existing digital divide and its trends, it also investigates the relationship between the digital divide and the digital opportunity index. A mathematical model based on analysis of the growing digital divide is presented as a possible tool for combating and eradicate the digital divide gap which is only possible if developing and poor nations take advantage of the digital opportunities that can transform them into global competitive partners in digital knowledge economy. (author)

  16. Measure the Performance of Reducing Digital Divide – the BSC and AHP Approach

    Directory of Open Access Journals (Sweden)

    Hsing-I Wang

    2011-03-01

    Full Text Available Digital divides are the byproducts of the development of information technologies and digitalization. What concern most of the governments and the international organizations are the disturbance of the advancement of national competitiveness as well as the improvement of human lives caused by the presence of digital divides.Countries world wide have proposed numerous of strategies to reduce digital divides. However, the absence of the follow-up of the performance of the strategies forms another issue in reducing digital divides. Previous researches built digital divide balance scorecard to realize the objectives as well as to improve the performance of the strategies. This research adopts the analytical hierarchy process to prioritize the performance indicators which have been determined in the digital divide balance scorecard. The architecture proposed by the research would be applied to examine the merits of the strategies.

  17. Dividing time: Concurrent timing of auditory and visual events by young and elderly adults

    OpenAIRE

    McAuley, J Devin; Miller, Jonathan P.; Wang, Mo; Kevin C.H. Pang

    2010-01-01

    This article examines age differences in individual’s ability to produce the durations of learned auditory and visual target events either in isolation (focused attention) or concurrently (divided attention). Young adults produced learned target durations equally well in focused and divided attention conditions. Older adults in contrast showed an age-related increase in timing variability in divided attention conditions that tended to be more pronounced for visual targets than for auditory ta...

  18. A low-power digital frequency divider for system-on-a-chip applications

    KAUST Repository

    Omran, Hesham

    2011-08-01

    In this paper, an idea for a new frequency divider architecture is proposed. The divider is based on a coarse-fine architecture. The coarse block operates at a low frequency to save power consumption and it selectively enables the fine block which operates at the high input frequency. The proposed divider has the advantages of synchronous divider, but with lower power consumption and higher operation speed. The design can achieve a wide division range with a minor effect on power consumption and speed. The architecture was implemented on a complex programmable logic device (CPLD) to verify its operation. Experimental measurements validate system operation with power reduction greater than 40%. © 2011 IEEE.

  19. Water Wisdom: 23 Stand-Alone Activities on Water Supply and Water Conservation for High School Students. 2nd Edition.

    Science.gov (United States)

    Massachusetts State Water Resources Authority, Boston.

    This water conservation education program for high schools consists of both stand-alone activities and teacher support materials. Lessons are divided into six broad categories: (1) The Water Cycle; (2) Water and Society; (3) Keeping Water Pure; (4) Visualizing Volumes; (5) The Economics of Water Use; and (6) Domestic Water Conservation. The…

  20. 100kW dummy load using water for a klystron modulator

    International Nuclear Information System (INIS)

    A dummy load capable of handling the peak voltage of 37 kV and the average power of 100 kW using water as a resistor has been designed and constructed to perform the high-power tests of an X-band klystron modulator. Two coaxial electrodes are used to make the dummy load in a compact size. The load impedance is regulated in the range of 5 ? 12 ? stably. (author)

  1. Combination N-Way Power Divider/Combiner and Noninvasive Reflected Power Detection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An N-way RF/microwave power divider/combiner utilizes one input and N outputs, or conversely N inputs and one output to divide (or combine) RF/microwave power while...

  2. Social Impact of the "Digital Divide" in a Central-Eastern European Country.

    Science.gov (United States)

    Dragulanescu, Nicolae-George

    2002-01-01

    Discusses the social impact of the digital divide in Central-Eastern European countries as well as between them and industrialized developed countries, based on experiences in Romania. Highlights include facts relating to digital divide worldwide; transition to a democratic and market-based economy and from socialism to capitalism; barriers to…

  3. Divided Plato

    International Nuclear Information System (INIS)

    His experience as nuclear physicist, univerity professor, and research promoter recommend the author as a partner in the discussion on progress. He shows what kind of man a scientist is, which motivations he has, what he can do. He explains how it is possible even today to find simple ways to the unknown, how the new, the unforeseeable comes into being. And he gives stimuli to and examples of the work of scientists, his responsibility and his contribution to the application of knowledge, - for instance in the field of nuclear energy - and of the contributions of science to problems of economy and politics. (orig.)

  4. Mobility Divides

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2013-01-01

    Contemporary mobilities are cultural and social manifestations, and the mobile practices in the everyday life of billions of humans are re-configuring senses of place, self, other and relationships to the built environment. The way ‘mobile situations’ are staged in designed and built environments are increasingly becoming ‘second nature’ but also expressions of power, exclusion, and difference. In this talk I will be applying a perspective of ‘mobile situationism’ illustrating how mobile everyda...

  5. ASSESSING THE NEED, CHALLENGES AND SOLUTIONS TO BRIDGE THE DIVIDE OF DIGITAL INEQUALITY

    Directory of Open Access Journals (Sweden)

    Surya Singh

    2015-03-01

    Full Text Available Digital resources are playing a gigantic role in the present Knowledge Society. But there is wide disparity in terms of access to the digital technology. In one hand we have very skilled human resource which is making use of digital resources effectively; on the other hand we have group of people those who don’t have skill and access to the digital technology. In 21st century’s knowledge society, digital resources dividing human society in to two groups called ‘Digital Haves’and ‘Digital Have Not’s. The is the “Digital Divide’’that refers to the difference between individuals within or outside the families, businesses and geographic areas in various socio-economic levels with regard to both their opportunities in accessing Information and Communication Technologies (ICTs and also the use of the internet for multiple purposes. This paper focuses on bridging the Digital Divide. One of the main challenges is frightening gap between the information have-s and information have-nots, what we call the digital divide. Purpose of this study is to highlight and identify some major issues of digital divide and efforts to bridging the digital divide. It concludes by providing the some possible solutions in bridging the digital divide.

  6. Illusory recollection in older adults and younger adults under divided attention.

    Science.gov (United States)

    Skinner, Erin I; Fernandes, Myra A

    2009-03-01

    The authors investigated the effect of divided attention, study-list repetition, and age on recollection and familiarity. Older and younger adults under full attention and younger adults under divided attention at study viewed word lists highly associated with a single unstudied word (critical lure) once or three times, and subsequently performed a remember-know recognition test. Younger adults made fewer false remember responses to critical lures from repeated study lists, whereas younger adults under divided attention and older adults both showed an increase with repetition. Findings suggest older adults' susceptibility to illusory memories is related to a deficit in available attention during encoding. PMID:19290753

  7. Poor need knowledge not only technology to bridge digital divide: experts

    CERN Multimedia

    2003-01-01

    "Developing countries need to gain knowledge rather than technology to latch onto the booming information society, experts said Monday ahead of a major conference on bridging the digital divide between rich and poor" (1/2 page).

  8. Drosophila midgut homeostasis involves neutral competition between symmetrically dividing intestinal stem cells

    OpenAIRE

    de Navascués, Joaquín; Perdigoto, Carolina N.; Bian, Yu; Schneider, Markus H; Bardin, Allison J; Martínez-Arias, Alfonso; Simons, Benjamin D.

    2012-01-01

    Quantitative analyses on clonal fate of Drosophila midgut intestinal stem cells suggest that neutral competition of symmetrically dividing cells contributes to physiological tissue dynamics. The study thus adds to current models on stem-cell behaviour in flies and vertebrates.

  9. Divide-and-Conquer 3D Convex Hulls on the GPU

    OpenAIRE

    White, Jeffrey M.; Wortman, Kevin A.

    2012-01-01

    We describe a pure divide-and-conquer parallel algorithm for computing 3D convex hulls. We implement that algorithm on GPU hardware, and find a significant speedup over comparable CPU implementations.

  10. Variable-geometry turbocharger with asymmetric divided volute for engine exhaust gas pulse optimization

    Science.gov (United States)

    Serres, Nicolas (Epinal, FR)

    2010-11-09

    A turbine assembly for a variable-geometry turbocharger includes a turbine housing defining a divided volute having first and second scrolls, wherein the first scroll has a substantially smaller volume than the second scroll. The first scroll feeds exhaust gas to a first portion of a turbine wheel upstream of the throat of the wheel, while the second scroll feeds gas to a second portion of the wheel at least part of which is downstream of the throat. Flow from the second scroll is regulated by a sliding piston. The first scroll can be optimized for low-flow conditions such that the turbocharger can operate effectively like a small fixed-geometry turbocharger when the piston is closed. The turbine housing defines an inlet that is divided by a dividing wall into two portions respectively feeding gas to the two scrolls, a leading edge of the dividing wall being downstream of the inlet mouth.

  11. The effect of divided attention on false memory depends on how memory is tested.

    Science.gov (United States)

    Dewhurst, Stephen A; Barry, Christopher; Swannell, Ellen R; Holmes, Selna J; Bathurst, Gemma L

    2007-06-01

    In three experiments, we investigated the effects of divided attention on false memory, using the Deese/Roediger-McDermott (DRM) paradigm. In Experiments 1 and 2, participants studied six DRM lists with full attention and six in one of two divided-attention conditions (random number generation or digit monitoring). Both divided-attention conditions increased false recall of related words (Experiment 1) but reduced false recognition (Experiment 2). These results were confirmed in Experiment 3, in which the type of secondary task was manipulated within groups. We argue that the increase in false recall with divided attention reflects a change in participants' response criterion, whereas the decrease in false recognition occurs because the secondary tasks prevent participants from generating associates of the words presented at study. PMID:17848024

  12. 5 CFR Appendix A to Subpart F of... - Recommended Language for Court Orders Dividing Employee Annuities

    Science.gov (United States)

    2010-01-01

    ...Recommended Language for Court Orders Dividing Employee Annuities A Appendix A to Subpart F of Part... Terminology Used in Court Orders Affecting Employee Annuities or Refunds of Employee Contributions Pt. 838, Subpt. F,...

  13. Harmonic-suppressed quadrature-input frequency divider for OFDM systems

    International Nuclear Information System (INIS)

    A fully balanced harmonic-suppressed quadrature-input frequency divider is proposed. The frequency divider improves the quadrature phase accuracy at the output by using both input I/Q signals. Compared with conventional dividers, the circuit achieves an output I/Q phase sequence that is independent of the input I/Q phase sequence. Moreover, the third harmonic is effectively suppressed by employing a double degeneration technique. The design is fabricated in TSMC 0.13-?m CMOS and operated at 1.2 V. While locked at 8.5 GHz, the proposed divider measures a maximum third harmonic rejection of 45 dB and a phase noise of ?124 dBc/Hz at a 10 MHz offset. The circuit achieves a locking range of 15% while consuming a total current of 4.5 mA. (semiconductor integrated circuits)

  14. Information Resources Column: "The Digital Divide: How Wide and How Deep?

    OpenAIRE

    Schloman, B

    2004-01-01

    The complexity of the issues that make up the digital divide problem is better understood today. It is no longer sufficient to see it simply as a disparity of access to computer technology. Rather, there is recognition that having meaningful support for using the technology is also an essential ingredient for getting online. The digital divide is a global problem, but even in the technology rich United States the situation is troubling. Recent studies have shown that within the United States,...

  15. Effective use: A community informatics strategy beyond the Digital Divide (originally published in December 2003)

    OpenAIRE

    Gurstein, Michael

    2007-01-01

    A huge industry has been created responding to the perceived social malady, the "Digital Divide". This paper examines the concepts and strategies underlying the notion of the Digital Divide and concludes that it is little more than a marketing campaign for Internet service providers. The paper goes on to present an alternative approach - that of "effective use" - drawn from community informatics theory which recognizes that the Internet is not simply a source of information, but also a fundam...

  16. The robotics divide a new frontier in the 21st century?

    CERN Document Server

    López Peláez, Antonio

    2013-01-01

    Analyzes how robotics will shape our societies in the twenty-first century; a time when industrial and service robotics, particularly for military and aerospace purposes, will become an essential technology Examines an emerging divide: the "robotics divide"; a phenomenon linked to the model to integrate advanced robotics in economic, social and military spheres Focuses on the main technological trends in the field of robotics, and the impact that robotics will have on different facets of social life

  17. On the Right Side for the Wrong Reason : Friedman on the Marshall-Walras divide

    OpenAIRE

    De Vroey, Michel

    2004-01-01

    The aim of this article is to assess Friedman's claim, put forward in his 1949 article on the Marshallian demand curve, that there is a methodological divide between the Marshallian and Walrasian approaches. Friedman's argument will be critically examined and compared with the views he expressed in other articles written around the same time. My evaluation will lead to a mixed conclusion. Positively, Friedman must be hailed for having brought the Marshall?Walras divide to the forefront....

  18. Divided Government, Legislative Productivity, and Policy Change in the USA and France

    OpenAIRE

    Baumgartner, Frank; Brouard, Sylvain; Grossman, Emiliano; Lazardeux, Sébastien; Moody, Jonathan

    1988-01-01

    The concept of "divided government" is more complicated than scholars have allowed. In the USA, truly unified government, where the president enjoys a filibuster-proof majority in the Senate as well as a majority in the House, is rare. In France, truly unified government has been more common, but divided government has also occurred several times. Democratic governance requires that parties address important issues and they do so regardless of the patterns of institutional control. Neverthele...

  19. Playing for peace? The relationship of sport to peacebuilding in divided societies

    OpenAIRE

    Norman, Mark

    2009-01-01

    As the use of sport in pursuit of development objectives becomes increasingly common, there is a pressing need to determine if and how sport can be productively used to promote peace in divided societies. While sport is commonly presented as an inherently positive phenomenon, a deeper examination of its role in divided societies reveals a conflicted picture of its value. While it can help to build bridges between antagonistic groups, sport can also exacerbate conflict and reinforce division. ...

  20. Exploring the Future of the Digital Divide through Ethnographic Futures Research

    OpenAIRE

    Mitchell, Matthew

    2002-01-01

    This study examines leaders who work for social change in an information society. Grounded in the notion that leadership and social change are necessarily future oriented, this study attempts to learn how those who lead the effort to ameliorate the digital divide in Washington State perceive the optimistic, pessimistic, and most probable futures. In this study, the digital divide is framed as a social problem that is caused, in part, by inequities in the ability to access and to use informati...

  1. Are egalitarians really vulnerable to the Levelling-Down Objection and the Divided World Example?

    OpenAIRE

    Subramanian, S

    2011-01-01

    This essay is a quick critique of one aspect of Derek Parfit’s criticism of Egalitarianism in his larger consideration of the claims of, and distinction between, Prioritarianism and Egalitarianism. It reviews issues relating to the ‘Levelling Down Objection’ and the ‘Divided World Example’. More specifically, it is argued that the Levelling Down Objection is a serious problem only for Pure Telic Egalitarianism, not for Pluralist Telic Egalitarianism; and thateven in a Divided World, one can ...

  2. Kinematic Identification of Parallel Mechanisms by a Divide and Conquer Strategy

    DEFF Research Database (Denmark)

    Durango, Sebastian; Restrepo, David; Ruiz, Oscar; Restrepo-Giraldo, John Dairo; Achiche, Sofiane

    2010-01-01

    This paper presents a Divide and Conquer strategy to estimate the kinematic parameters of parallel symmetrical mechanisms. The Divide and Conquer kinematic identification is designed and performed independently for each leg of the mechanism. The estimation of the kinematic parameters is performed using the inverse calibration method. The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix. With respect to traditional id...

  3. Statistical and numerical methods to improve the transient divided bar method

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, S.B.

    The divided bar method is a commonly used method to measure thermal conductivity of rock samples in laboratory. We present improvements to this method that allows for simultaneous measurements of both thermal conductivity and thermal diffusivity. The divided bar setup is run in a transient mode and the temperature distribution in the stack is simulated by Finite Element Modeling (FEM). A Markov Chain Monte Carlo Metropolis Hastings (MCMCMH) algorithm is used to estimate the thermal parameters of the sample.

  4. Modulation of early cortical processing during divided attention to non-contiguous locations

    OpenAIRE

    Frey, Hans-Peter; Schmid, Anita M.; Murphy, Jeremy W.; Molholm, Sophie; Lalor, Edmund C; John J. Foxe

    2014-01-01

    We often face the challenge of simultaneously attending to multiple non-contiguous regions of space. There is ongoing debate as to how spatial attention is divided under these situations. While for several years the predominant view was that humans could divide the attentional spotlight, several recent studies argue in favor of a unitary spotlight that rhythmically samples relevant locations. Here, this issue was addressed using high-density electrophysiology in concert with the multifocal m-...

  5. Cortical sites of sustained and divided attention in normal elderly humans

    DEFF Research Database (Denmark)

    Johannsen, Peter; Jakobsen, Johannes Klitgaard; Bruhn, Peter; Hansen, Søren Baarsgaard; Gee, A; Stødkilde-Jørgensen, Hans; Gjedde, Albert

    1997-01-01

    Human brain mechanisms subserving attention have been assigned to prefrontal, midfrontal, and posterior parietal cortices, as well as to the anterior cingulate and the thalamus. To map these mechanisms in the brain, most studies have used selective attention tasks; few studies have mapped the brain under sustained or divided attention. The present study was designed to create maps of regional activity associated with sustained and divided attention using two different sensory modalities: visual ...

  6. Exergy loss analysis of heat transfer across the wall of the dividing-wall distillation column

    International Nuclear Information System (INIS)

    The dividing-wall distillation column is thermodynamically equivalent to the Petlyuk column on the condition that no heat transfer is allowed across the dividing wall. However, better energy efficiency of the column may be obtained if heat transfer occurs within a certain part of the wall. The effects of heat transfer across the dividing wall can be analyzed by using the column grand composite curve (CGCC). The heat transfer potential across the wall can be observed by looking at the CGCC of both column sections alongside the dividing wall. However, the possibility of whether heat should be added or rejected at any stage is not clearly known ahead of the CGCC. Consequently, in this work, the exergy analysis is applied to the dividing-wall column in order to determine whether heat should be added or rejected at any particular stage. Also, the minimum exergy loss value in the column is set as the criterion for determining the heat load targets at any stage. These load targets can then be plotted as a T-H profile similar to the CGCC. This methodology was reported to successfully apply to the column with multiple feeds and products. After having identified the locations and quantities of the feasible heat transfer across the dividing wall, the benefits are discussed via three case studies

  7. Large-scale atomistic simulations of nanostructured materials based on divide-and-conquer density functional theory

    Directory of Open Access Journals (Sweden)

    Vashishta P.

    2011-05-01

    Full Text Available A linear-scaling algorithm based on a divide-and-conquer (DC scheme is designed to perform large-scale molecular-dynamics simulations, in which interatomic forces are computed quantum mechanically in the framework of the density functional theory (DFT. This scheme is applied to the thermite reaction at an Al/Fe2O3 interface. It is found that mass diffusion and reaction rate at the interface are enhanced by a concerted metal-oxygen flip mechanism. Preliminary simulations are carried out for an aluminum particle in water based on the conventional DFT, as a target system for large-scale DC-DFT simulations. A pair of Lewis acid and base sites on the aluminum surface preferentially catalyzes hydrogen production in a low activation-barrier mechanism found in the simulations

  8. Particle-in-cell simulations of electron beam control using an inductive current divider

    Science.gov (United States)

    Swanekamp, S. B.; Angus, J. R.; Cooperstein, G.; Ottinger, P. F.; Richardson, A. S.; Schumer, J. W.; Weber, B. V.

    2015-11-01

    Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam's return current. The current divider concept was proposed and studied theoretically in a previous publication [Swanekamp et al., Phys. Plasmas 22, 023107 (2015)]. A central post carries a portion of the return current (I1), while the outer conductor carries the remainder (I2) with the injected beam current given by Ib = I1 + I2. The simulations are in agreement with the theory which predicts that the total force on the beam trajectory is proportional to (I2-I1) and the force on the beam envelope is proportional to Ib. Independent control over both the current density and the beam angle at the target is possible by choosing the appropriate current-divider geometry. The root-mean-square (RMS) beam emittance (?RMS) varies as the beam propagates through the current divider to the target. For applications where control of the beam trajectory is desired and the current density at the target is similar to the current density at the entrance foil, there is a modest 20% increase in ?RMS at the target. For other applications where the beam is pinched to a current density ˜5 times larger at the target, ?RMS is 2-3 times larger at the target.

  9. Brain activity during divided and selective attention to auditory and visual sentence comprehension tasks

    Directory of Open Access Journals (Sweden)

    Mona Moisala

    2015-02-01

    Full Text Available Using functional magnetic resonance imaging, we measured brain activity of human participants while they performed a sentence congruence judgment task in either the visual or auditory modality separately, or in both modalities simultaneously. Significant performance decrements were observed when attention was divided between the two modalities compared with when one modality was selectively attended. Compared with selective attention (i.e., single tasking, divided attention (i.e., dual-tasking did not recruit additional cortical regions, but resulted in increased activity in medial and lateral frontal regions which were also activated by the component tasks when performed separately. Areas involved in semantic language processing were revealed predominantly in the left lateral prefrontal cortex by contrasting incongruent with congruent sentences. These areas also showed significant activity increases during divided attention in relation to selective attention. In the sensory cortices, no crossmodal inhibition was observed during divided attention when compared with selective attention to one modality. Our results suggest that the observed performance decrements during dual-tasking are due to interference of the two tasks because they utilize the same part of the cortex. Moreover, semantic dual-tasking did not appear to recruit additional brain areas in comparison with single tasking, and no crossmodal inhibition was observed during intermodal divided attention.

  10. Kinematic Identification of Parallel Mechanisms by a Divide and Conquer Strategy

    DEFF Research Database (Denmark)

    Durango, Sebastian; Restrepo, David

    2010-01-01

    This paper presents a Divide and Conquer strategy to estimate the kinematic parameters of parallel symmetrical mechanisms. The Divide and Conquer kinematic identification is designed and performed independently for each leg of the mechanism. The estimation of the kinematic parameters is performed using the inverse calibration method. The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix. With respect to traditional identification methods the main advantages of the proposed Divide and Conquer kinematic identification strategy are: (i) reduction of the kinematic identification computational costs, (ii) improvement of the numerical efficiency of the kinematic identification algorithm and, (iii) improvement of the kinematic identification results. The contributions of the paper are: (i) The formalization of the inverse calibration method as the Divide and Conquer strategy for the kinematic identification of parallel symmetrical mechanisms and, (ii) a new kinematic identification protocol based on the Divide and Conquer strategy. As an application of the proposed kinematic identification protocol the identification of a planar 5R symmetrical mechanism is simulated. The performance of the calibrated mechanism is evaluated by updating the kinematic model with the estimated parameters and developing simulations.

  11. The high voltage divider - a tool for comparison of measurement equipment in diagnostic radiology

    International Nuclear Information System (INIS)

    The high voltage divider (HVD) is designed for control and analysis of the characteristics of the X-ray generator. The low voltage analogous signals produced by the divider are proportional to the high voltage (kVp) applied to the x-ray tube by a ratio 1:1000 or 1:10000 and can be measured with external test devices like storage oscilloscope (or digital multimeter). The exposure duration and the wave form may be visualized, too. Apart of this invasive way the high voltage also may be measured non-invasively by means of appropriate devices as well as indirectly through calculations. Since the invasive method of measurement with the high voltage divider is distinguished by a high accuracy, it may be utilized as an effective tool for calibration of different devices and for comparison of the measurement methods. (authors)

  12. An InGaAs/InP 40 GHz CML static frequency divider

    Energy Technology Data Exchange (ETDEWEB)

    Su Yongbo; Jin Zhi; Cheng Wei; Ge Ji; Wang Xiantai; Chen Gaopeng; Liu Xinyu [Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Xu Anhuai; Qi Ming, E-mail: jinzhi@ime.ac.cn [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2011-03-15

    Static frequency dividers are widely used as a circuit performance benchmark or figure-of-merit indicator to gauge a particular device technology's ability to implement high speed digital and integrated high performance mixed-signal circuits. We report a 2 : 1 static frequency divider in InGaAs/InP heterojunction bipolar transistor technology. This is the first InP based digital integrated circuit ever reported on the mainland of China. The divider is implemented in differential current mode logic (CML) with 30 transistors. The circuit operated at a peak clock frequency of 40 GHz and dissipated 650 mW from a single -5 V supply. (semiconductor integrated circuits)

  13. Uses of Information and Communication Technologies in Europe's Higher Education Institutions: From Digital Divides to Digital Trajectories

    OpenAIRE

    Adel Ben Youssef; Ludovic Ragni

    2008-01-01

    ABSTRACT This paper has two objectives, firstly, to identify the three basic levels of educational digital divides and to discuss them in the context of the European Union, and secondly, to develop an alternative hypothesis for educational digital trajectories instead of looking at educational divides.Section one identifies the three levels of digital divides. The first level of educational digital divide concerns differences in ICT equipment. We identify the sources and the mechanisms that h...

  14. Marker-independent Method for Isolating Slow-Dividing Cancer Stem Cells in Human Glioblastoma

    Directory of Open Access Journals (Sweden)

    Cristina Richichi

    2013-07-01

    Full Text Available Glioblastoma (GBM is a devastating brain tumor with a poor survival outcome. It is generated and propagated by a small subpopulation of rare and hierarchically organized cells that share stem-like features with normal stem cells but, however, appear dysregulated in terms of self-renewal and proliferation and aberrantly differentiate into cells forming the bulk of the disorganized cancer tissues. The complexity and heterogeneity of human GBMs underlie the lack of standardized and effective treatments. This study is based on the assumption that available markers defining cancer stem cells (CSCs in all GBMs are not conclusive and further work is required to identify the CSC. We implemented a method to isolate CSCs independently from cell surface markers: four patient-derived GBM neurospheres containing stem, progenitors, and differentiated cells were labeled with PKH-26 fluorescent dye that reliably selects for cells that divide at low rate. Through in vitro and in vivo assays, we investigated the growth and self-renewal properties of the two different compartments of high- and slow-dividing cells. Our data demonstrate that only slow-dividing cells retain the ability of a long-lasting self-renewal capacity after serial in vitro passaging, while high-dividing cells eventually exhaust. Moreover, orthotopic transplantation assay revealed that the incidence of tumors generated by the slow-dividing compartment is significantly higher in the four patient-derived GBM neurospheres analyzed. Importantly, slow-dividing cells feature a population made up of homogeneous stem cells that sustain tumor growth and therefore represent a viable target for GBM therapy development.

  15. Numerical Analysis of Pulsatile Blood Flow in a Stented Human Coronary Artery with a Flow Divider

    Directory of Open Access Journals (Sweden)

    Vahab Dehlaghi

    2007-01-01

    Full Text Available Shear stress is known to play a central role in restenosis formation and is sensitive to stent geometry. Local flow alterations created by a different stents without and with flow divider were studied to compare the hemodynamic effects of Stent design properties on restenosis in stented human coronary artery. Blood pressure and shear stress values were computed in three different sites, including stented arterial segment, pre-stent and post-stent regions using computational fluid dynamics. Blood flow was assumed as pulsatile, incompressible and Newtonian flow. Rigid boundary conditions were assumed for all models. The governing Navier-Stokes equations were solved using commercial software package (Fluent V6.0.12. Stents are assumed with real structure and modeled using the commercial software package (Gambit, V2.0. The arterial wall shear stress distribution was investigated in three major regions and critical sites were located. It is concluded that the wall shear stress between stent struts was sensitive to strut spacing, profile of strut, number of struts and curvature. Our 3D computational fluid dynamics modeling demonstrate that with increasing the angle between two sides of the stent strut the percentage of intrastrut area that exposed to critical value of WSS decreases. By application of a flow divider, the wall shear stress in stented segment increases markedly and so is the pressure gradient in stented segment. Flow divider influences the blood flow pattern in proximal of stented segment. In this section, the WSS increases with application of the flow divider. The results for different diameters of flow divider show that optimum diameter for flow divider is D/3.

  16. Study of timing voltage divider system of PMT for neutron wall at CSR terminal

    International Nuclear Information System (INIS)

    On the outer-target experimental terminal in Heavy Ion Cooling Storage Ring at Lanzhou, an experimental setup for the study of RIB physics and the investigation of features of the asymmetric nuclear matter by means of RIB is highly required. The neutron detection wall is a main part of the detection equipment, in which there are 1000 photomultipliers serving as signal readout devices. The PMTs' voltage divider is studied. Both design parameters and the measured results show that the timing-type voltage divider is more suitable for detecting time signals. (authors)

  17. Gradations in digital inclusion: children, young people and the digital divide

    OpenAIRE

    Livingstone, Sonia; Helsper, Ellen

    2007-01-01

    Little academic and policy attention has addressed the `digital divide' among children and young people. This article analyses findings from a national survey of UK 9—19-year-olds that reveal inequalities by age, gender and socioeconomic status in relation to their quality of access to and use of the internet. Since both the extent of use and the reasons for low- and non-use of the internet vary by age, a different explanation for the digital divide is required for children compared with adul...

  18. Ultralow phase noise microwave generation with an Er:fiber-based optical frequency divider

    CERN Document Server

    Quinlan, F; Kirchner, M S; Taylor, J A; Thorpe, M J; Lemke, N; Ludlow, A D; Jiang, Y; Oates, C W; Diddams, S A

    2011-01-01

    We present an optical frequency divider based on a 200 MHz repetition rate Er:fiber mode-locked laser that, when locked to a stable optical frequency reference, generates microwave signals with absolute phase noise that is equal to or better than cryogenic microwave oscillators. At 1 Hz offset from a 10 GHz carrier, the phase noise is below -100 dBc/Hz, limited by the optical reference. For offset frequencies > 10 kHz, the phase noise is shot noise limited at -145 dBc/Hz. An analysis of the contribution of the residual noise from the Er:fiber optical frequency divider is also presented.

  19. Fabrication of nanowire electronics on nonconventional substrates by water-assisted transfer printing method

    Science.gov (United States)

    Lee, Chi Hwan; Kim, Dong Rip; Zheng, Xiaolin

    2015-06-01

    We report a simple, versatile, and wafer-scale water-assisted transfer printing method (WTP) that enables the transfer of nanowire devices onto diverse nonconventional substrates that were not easily accessible before, such as paper, plastics, tapes, glass, polydimethylsiloxane (PDMS), aluminum foil, and ultrathin polymer substrates. The WTP method relies on the phenomenon of water penetrating into the interface between Ni and SiO2. The transfer yield is nearly 100%, and the transferred devices, including NW resistors, diodes, and field effect transistors, maintain their original geometries and electronic properties with high fidelity.

  20. From Atoms to Bits: Consequences of the Emerging Digital Divide in India.

    Science.gov (United States)

    Singh, Jagtar

    2002-01-01

    Discusses the impact of information and communication technologies (ICTs) and the digital divide in India. Considers the impact of information technologies, including the Internet and the Web, on the life and work of people; digital determinism; library and information infrastructure and superstructure; digital library initiatives; and the need…

  1. Advanced AODV Protocol for Identify Victim Nodes Using Divide and Conquer Strategy-in MANET

    Directory of Open Access Journals (Sweden)

    S. Hemalatha

    2014-10-01

    Full Text Available Objective of this study is there are many protocols have been proposed in Ad-hoc network, but none of the protocol is working under the principle of handling and checking on packet delivery. We have developed a routing protocol called the Advanced Ad-hoc on demand Vector protocol. The working principle of this protocol is checking the packet delivery to the destination. If any one of the nodes in the route is not forwarding the packet, that corresponding node will be identified and redirect the packet to the new route. For doing this checking this protocol uses divide and conquer strategy. The number hop between the source to destination is divided into two halves and check whether the up to the middle node the packet are flowing in a proper order or not. Recursively doing the divide and conquer of the route path, can identify the node which is not forward the packet to the next node. The design of this protocol contains several stages from path discovery, packet transmits, apply divide and conquer strategy on route, identify the victim node which is not forward the packet, redirect the new path, alert all the nodes about the victim node. Finally performance graph has been given compared with AODV protocol.

  2. Comments on John Willinsky's Learning to Divide the World: Education at Empire's End

    Science.gov (United States)

    Wang, Tsung Juang

    2006-01-01

    John Willinsky's view that imperialism and its legacy remain the driving force that divides the world into "superior" and "inferior" cultures fails to take into account other forces that also encourage peoples of different cultures to emphasize the differences between themselves. He is correct in noting that imperialism led to much injustice and…

  3. Crossing the Digital Divide Safely and Trustingly: How Ecologies of Learning Scaffold the Journey

    Science.gov (United States)

    Henning, Elizabeth; Van der Westhuizen, Duan

    2004-01-01

    The article addresses the issue of "learning to elearn" in borderless programs in a globalised learning landscape and the associated problems of scaffolding the journey across the digital divide. The authors argue that the assumption underlying such courses is that cross-cultural programs are viable because they are conceived and designed to be…

  4. Choice Issue Opens Rift in Missouri: Tax-Credit Scholarships Divide Black Caucus

    Science.gov (United States)

    Viadero, Debra

    2006-01-01

    The debate over a school choice bill in the Missouri legislature has opened a bitter rift among some of the state's top Black elected officials and reflects a larger divide among African-Americans over school choice nationwide. The bill, which is similar to programs that are growing in popularity in other states, would provide tax credits for…

  5. Reassessing the Racial Divide in Support for Capital Punishment: The Continuing Significance of Race

    Science.gov (United States)

    Unnever, James D.; Cullen, Francis T.

    2007-01-01

    This project investigates the racial divide in support for capital punishment. The authors examine whether race has a direct effect on support for capital punishment and test whether the influence of race varies across class, being a native southerner, confidence in government officials, political orientation, and religious affiliation. Using data…

  6. Closing the Digital Divide: Education Telecommunications Systems and Possibilities in Western Australia

    Science.gov (United States)

    Trinidad, Sue

    2007-01-01

    The research reported in this paper considers the current telecommunications network for the three education systems of state, independent and catholic schools in Western Australia as well as drawing on the personal experiences of teachers in these systems as the government attempts to close the digital divide with its Networking the Nation…

  7. The Electoral College Exacerbates the Red-Blue Divide and Disenfranchises Ethnic Minorities

    Science.gov (United States)

    Webster, Gregory D.

    2007-01-01

    Comments on the article by Seyle and Newman "A house divided? The psychology of red and blue America,". Seyle and Newman argued that perceiving the American political landscape in terms of red and blue (to describe conservative and liberal perspectives, respectively) might unnecessarily pigeonhole people's dynamic social identities into one of two…

  8. The Racial Divide in Support for the Death Penalty: Does White Racism Matter?

    Science.gov (United States)

    Unnever, James D.; Cullen, Francis T.

    2007-01-01

    Using data from the 2000 National Election Study, this research investigates the sources of the racial divide in support for capital punishment with a specific focus on white racism. After delineating a measure of white racism, we explore whether it can account for why a majority of African Americans oppose the death penalty while most whites…

  9. The Digital Health Divide: Evaluating Online Health Information Access and Use among Older Adults

    Science.gov (United States)

    Hall, Amanda K.; Bernhardt, Jay M.; Dodd, Virginia; Vollrath, Morgan W.

    2015-01-01

    Objective: Innovations in health information technology (HIT) provide opportunities to reduce health care spending, improve quality of care, and improve health outcomes for older adults. However, concerns relating to older adults' limited access and use of HIT, including use of the Internet for health information, fuel the digital health divide…

  10. Sociological implications of scientific publishing: Open access, science, society, democracy and the digital divide

    OpenAIRE

    Herb, Ulrich

    2010-01-01

    Claims for open access are mostly underpinned with 1. science—related arguments (open access accelerates scientific communication); 2. financial arguments (open access relieves the serials crisis); 3. social arguments (open access reduces the digital divide); 4. democracy—related arguments (open access facilitates participation); and, 5. socio—political arguments (open access levels disparities). Using sociological concepts and notions, this article focuses ...

  11. Gender Divide and Acceptance of Collaborative Web 2.0 Applications for Learning in Higher Education

    Science.gov (United States)

    Huang, Wen-Hao David; Hood, Denice Ward; Yoo, Sun Joo

    2013-01-01

    Situated in the gender digital divide framework, this survey study investigated the role of computer anxiety in influencing female college students' perceptions toward Web 2.0 applications for learning. Based on 432 college students' "Web 2.0 for learning" perception ratings collected by relevant categories of "Unified Theory of Acceptance and Use…

  12. Nuclear Technology. Course 27: Metrology. Module 27-2, Fixed Gages, Dividers, Calipers, and Micrometers.

    Science.gov (United States)

    Selleck, Ben; Espy, John

    This second in a series of eight modules for a course titled Metrology dscribes fixed gages, dividers, calipers, vernier and dial calipers, and micrometers. The module follows a typical format that includes the following sections: (l) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject matter, (6)…

  13. An Analysis of the North Carolina Cooperative Extension Service's Role in Bridging the Digital Divide

    Science.gov (United States)

    Alston, Antoine J.; Hilton, Lashawn; English, Chastity Warren; Elbert, Chanda; Wakefield, Dexter

    2011-01-01

    The study reported here sought to determine the perception of North Carolina County Cooperative Extension directors in regard to the North Carolina Cooperative Extension Service's role in bridging the digital divide. It was perceived by respondents that variables such as income, education, gender, disability status, race/ethnicity, age, and…

  14. Soul and Role Dialogues in Higher Education: Healing the Divided Self

    Science.gov (United States)

    Michalec, Paul; Brower, Gary

    2012-01-01

    A group of faculty and staff gather in a conference room in the student union to share experiences with the soul-role divide at work and in the classroom. The meeting begins with a reminder of the group's conversational norms that invite deep reflection and a safe place for the soul. The purpose of the meeting is exploring the deep heartfelt and…

  15. Characterization of polyester with fiberglass materials as reinforcement in interior dividing walls

    OpenAIRE

    Santos, Tiago; Velosa, J. C.; Ramos, Lu??s F., ed. lit.; Fangueiro, Ra??l; Mendon??a, Paulo

    2012-01-01

    Some synthetic fibers present better mechanical performance compared with the natural fibers. Therefor research works were carried out to focus the characterization of polyester and glass fibers to be used as reinforcements in the internal dividing walls. Results from polyester fabrics made of compression with or without fiberglass were obtained.

  16. Divide and Conquer: the Quest for Compositional Design and Analysis (Dagstuhl Seminar 12511)

    OpenAIRE

    Huismann, Marieke; Jobstmann, Barbara; Schaefer, Ina; Stoelinga, Marielle

    2013-01-01

    On December 17 to 21, the Dagstuhl seminar "Divide and Conquer: the Quest for Compositional Design and Analysis" was organized. Topic was the compositionally, a central theme in computer science, but its applications, methods, techniques are scattered around many different disciplines. Therefore, this workshop brought together scientists from different disciplines, including deductive verification, model checking, software product lines, component interfaces.

  17. 76 FR 22075 - Divide Ranger District, Rio Grande National Forest; CO; Black Mesa Vegetation Management Project

    Science.gov (United States)

    2011-04-20

    The Divide Ranger District, Rio Grande National Forest, proposes to salvage timber stands killed or infested by spruce beetles; reduce fuel loading, particularly adjacent to private lands; cut potential hazard trees along private property, roads, and other infrastructure; and regenerate forested acres, as needed, to move toward the long-term desired conditions described in the Forest...

  18. Can't surf, won't surf: The digital divide in mental health

    OpenAIRE

    Ennis, Liam; Rose, Diana; Denis, Mike; Pandit, Ninjeri; Wykes, Til

    2012-01-01

    Background: New health information technology (HIT) increasingly plays a role in health care as technology becomes cheaper and more widespread. However, there is a danger that those who do not use or have access to technology will not benefit from HIT innovations, thus creating a “digital divide”.

  19. Public attitudes on the gay marriage debate are divided along party lines

    OpenAIRE

    Clements, Ben

    2012-01-01

    The Minister for Women and Equalities, Maria Miller, made a statement to Parliament yesterday about gay marriage. Following this Ben Clements analyses the attitudes towards gay marriage among party supporters and finds that party affiliation is a clear dividing line in public opinion on this issue.

  20. Quantifying and Mapping the Digital Divide from an Internet Point of View

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, R.Les; /SLAC; Khan, Shahryar; /NUST, Rawalpindi; Williams, Jerrod; /SLAC; Mehdi, Akbar; Kalim, Umar; Ali, Arshad; /NUST, Rawalpindi

    2008-09-18

    Quantitative knowledge of the magnitude, extent and trends of the Digital Divide are critical to understand and identify the regions most in need of help, to make rational decisions on how to address the problems and to make cases for executives, funding agencies and politicians. We report on a project (PingER) to measure the Digital Divide from the point of view of Internet performance. The PingER project has been measuring Internet performance since 1995 and with the increased emphasis on measuring and tracking the Digital Divide, it now covers over 700 hosts in over 150 countries that between them contain over 99% of the world's Internet connected population. In this paper we will describe the how PingER works, it deployment, the data analysis, and presentation. We also introduce a new PingER visualization tool (ViPER) that provides a more appealing interactive visualization of the PingER data and also works on mobile PDAs. We will also show results from PingER that illustrate the magnitude, extent and trends for the Digital Divide, and also compare PingER results with some human development and technology indices.

  1. Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems

    Energy Technology Data Exchange (ETDEWEB)

    Yin Jiangwei; Li Ning; Zheng Renliang; Li Wei; Ren Junyan, E-mail: lining@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2009-05-01

    This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 mum RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 x 0.28 mm{sup 2}. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

  2. Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems

    International Nuclear Information System (INIS)

    This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 ?m RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 x 0.28 mm2. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

  3. Combining polyamine depletion with radiation therapy for rapidly dividing head and neck tumors: Strategies for improved locoregional control

    International Nuclear Information System (INIS)

    Locoregional control is adversely affected as clonogens from rapidly proliferating tumors repopulate during a course of radiation therapy. The cytostatic agent ?-difluoromethylornithine (DFMO) was investigated for its capacity to slow proliferation kinetics in human squamous cell carcinomas (SSC) of the head and neck (H ampersand N), with the ultimate objective of improving locoregional control in rapidly dividing tumors treated with radiation therapy. Three human SSC cell lines established from primary H ampersand N tumors were evaluated in vitro (cell culture) and in vivo (SSC tumor xenografts in athymic mice) for the capacity of DFMO to induce growth inhibition. Flow cytometry analysis of SCC tumor growth kinetics and quantitative assessment of polyamine biosynthesis inhibition was performed to verify DFMO activity. DFMO effects on in vitro SSC radiosensitivity using clonogenic survival were also studied. A noncytotoxic exposure to DFMO (5mM x 72 hours) induced pronounced growth inhibition in all three SSC cell lines (70-90% at 7 days), and induced a 2-3 fold delay in volume doubling time for SCC tumor xenografts when administered orally in the drinking water (1.5%) to athymic mice. Kinetic analysis via flow cytometry confirmed that DFMO produced a lengthening of SCC cell cycle times, but did not alter in vitro radiosensitivity. Inhibition of ornithine decarboxylase (ODC) activity and depletion of endogenous polyamines (putrescine and spermidine), were confirmed in normal tissue (mouse skin) and in human SSC tumor xenografts of athymic mice receiving continuous oral DFMO. These data indicate that antiproliferative agents, such as DFMO, are capable of altering human SSC growth kinetics without altering intrinsic radiosensitivity. Such kinetic modulation may therefore provide a strategy to reduce the adverse impact of tumor cell proliferation during a radiotherapy treatment course for rapidly dividing tumors such as those in the H ampersand N. 33 refs., 5 figs., 3 tabs

  4. The household energy gap: examining the divide between habitual- and purchase-related conservation behaviours

    International Nuclear Information System (INIS)

    This paper examines the conceptual divide between energy saving behaviours in the home, relating to purchase-oriented behaviours and habitual action to conserve energy. Considerable empirical research indicates that this divide is of utility when characterising energy saving behaviour. However, little attention has been focused around the association between energy saving behaviours and other environmental actions. Accordingly, this paper examines the structural bases of energy conservation behaviours in the wider context of environmental behaviour. These findings are then used to examine the characteristics of energy savers as they relate to other environmental actions. Using cluster analysis, the paper defines a range of behavioural characteristics that transcend energy saving and other environmental actions. The use of such an approach to policy makers seeking to encourage energy conservation practices is discussed at the end of the paper

  5. Divide and rule: A qualitative analysis of the debriefing process in elite team sports.

    Science.gov (United States)

    Macquet, A-C; Ferrand, C; Stanton, N A

    2015-11-01

    This article aimed to gain an understanding of the process of debriefing during major competitions in elite team sports. Debrief interviews were conducted with 9 head coaches. The interview data were used to identify how head coaches divided up the tasks given to staff and team members prior to, and during the post-match debriefing. Results showed that debriefing consisted of two steps: preparation and presentation. Preparation referred to four successive tasks. Presentation to the team of players consisted of eight tasks relating to transformational and transactional styles of leadership. Coaches were shown to divide the labor within the staff and team. The data tend to support the view that in elite team sports, coaches are both transformational and transactional leaders, adapting their style of leadership to the situation, athletes and time available. This study provides insights into the task-work and team-work underlying team functioning and division of labor. PMID:26154201

  6. The quantum divide why Schrödinger's cat is either dead or alive

    CERN Document Server

    Gerry, Christopher C

    2013-01-01

    Using a selection of key experiments performed over the past 30 years or so, we present a discussion of the strikingly counter-intuitive phenomena of the quantum world that defy explanation in terms of everyday "common sense" reasoning, and we provide the corresponding quantum mechanical explanations with a very elementary use of associated formalism. Most, but certainly not all, of the experiments we describe are optical experiments involving a very small number of photons (particles of light). We begin with experiments on the wave-particle duality of electrons, proceed to experiments on the particle nature of light and single photon interference, delayed choice experiments and interaction-free detection, then go on to experiments involving the interference of two photons, quantum entanglement and Bell's Theorem, quantum teleportation, large-scale quantum effects and the divide between the classical and quantum worlds, addressing the question as to whether or not there is such a divide.

  7. IUE and Einstein survey of late-type giant and supergiant stars and the dividing line

    Science.gov (United States)

    Haisch, Bernhard M.; Bookbinder, Jay A.; Maggio, A.; Vaiana, G. S.; Bennett, Jeffrey O.

    1990-01-01

    Results are presented on an IUE UV survey of 255 late-type G, K, and M stars, complementing the Maggio et al. (1990) Einstein X-ray survey of 380 late-type stars. The large data sample of X-ray and UV detections make it possible to examine the activity relationship between the X-ray and the UV emissions. The results confirm previous finding of a trend involving a steeply-dropping upper envelope of the transition region line fluxes, f(line)/f(V), as the dividing line is approached. This suggests that a sharp decrease in maximum activity accompanies the advancing spectral type, with the dividing line corresponding to this steep gradient region. The results confirm the rotation-activity connection for stars in this region of the H-R diagram.

  8. [Formation, development and changes of the eye acupunture region-dividing acupoint location program].

    Science.gov (United States)

    Che, Jian; Tian, Wei-zhu

    2005-04-01

    Eye acupuncture, a micro-needling therapy, has been widely applied in clinical treatment for over 30 years. Its theoretic system, especially, the eye acupuncture region-dividing point location program has been revised for 2 times, and the third program with reasonability of acupoint distribution, strictness of angle of acupoint region is easily accepted by clinical workers. In the paper, the theoretical basis of professor Peng Jingshan's inspection of the eye for recognition of diseases, diagnosis of diseases and eye acupuncture therapy were explained, and the information, development and change of the eye acupuncture region-dividing acupoint location program were analyzed and the history of development of eye acupuncture were introduced so as to direct clinical application of eye acupuncture. PMID:16309109

  9. Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 March-June

    Science.gov (United States)

    Warner, Brian D.

    2015-10-01

    Lightcurves for 29 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2015 March-June. All but three were members of the Hungaria orbital group or collisional family and observed as part of an ongoing program to obtain data for spin axis and shape modeling. One Hungaria, (79472) 1998 AX4 showed signs of having a satellite. Analysis indicates it is a possible binary.

  10. Metacognition of Multi-Tasking: How Well Do We Predict the Costs of Divided Attention?

    OpenAIRE

    Finley, Jason R.; BENJAMIN, AARON S.; McCarley, Jason S.

    2014-01-01

    Risky multi-tasking, such as texting while driving, may occur because people misestimate the costs of divided attention. In two experiments, participants performed a computerized visual-manual tracking task in which they attempted to keep a mouse cursor within a small target that moved erratically around a circular track. They then separately performed an auditory n-back task. After practicing both tasks separately, participants received feedback on their single-task tracking performance and ...

  11. A dialectical take on artifact ecologies and the physical - digital divide

    DEFF Research Database (Denmark)

    BØdker, Susanne; Klokmose, Clemens Nylandsted

    In this position paper, we will present and discuss our understanding of artifact ecologies as we have developed it, rooted in activity theoretical HCI and dialectical thinking . Our basis is in the Human-Artifact Model, as well as well as cases where we have worked with artifact ecologies in analysis and design of computer mediated activity. The paper concludes with a positioning of our perspective vis-a-vis the notions of natural and blended interaction and the physical-digital divide

  12. Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 October-December

    Science.gov (United States)

    Warner, Brian D.

    2015-04-01

    Lightcurves for 18 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2014 October through December. All but one of the asteroids were a member of the Hungaria orbital group or collisional family, observed as follow-up to previous apparitions to check for undiscovered satellites, to improve previous binary discovery parameters, or to obtain data for spin axis and shape modeling.

  13. Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 December - 2015 March

    Science.gov (United States)

    Warner, Brian D.

    2015-07-01

    Lightcurves for 13 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2014 December through 2015 March. All but two were members of the Hungaria orbital group or collisional family and observed as follow-up to previous apparitions to check for undiscovered satellites or to obtain data for spin axis and shape modeling.

  14. Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 June-October

    Science.gov (United States)

    Warner, Brian D.

    2015-01-01

    Lightcurves for 24 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2014 June through October. Some objects were members of the Hungaria orbital group or collisional family, observed as follow-up to previous apparitions to check for undiscovered satellites, to improve previous binary discovery parameters, or to obtain data for spin axis and shape modeling.

  15. Divided Attention Improves Delayed, but Not Immediate Retrieval of a Consolidated Memory

    OpenAIRE

    Kessler, Yoav; Vandermorris, Susan; Gopie, Nigel; Daros, Alexander; Winocur, Gordon; Moscovitch, Morris

    2014-01-01

    A well-documented dissociation between memory encoding and retrieval concerns the role of attention in the two processes. The typical finding is that divided attention (DA) during encoding impairs future memory, but retrieval is relatively robust to attentional manipulations. However, memory research in the past 20 years had demonstrated that retrieval is a memory-changing process, in which the strength and availability of information are modified by various characteristics of the retrieval p...

  16. Mobile Phones Bridging the Digital Divide for Teens in the US?

    OpenAIRE

    Katie Brown; Campbell, Scott W.; Rich Ling

    2011-01-01

    In 2009, just 27% of American teens with mobile phones reported using their devices to access the internet. However, teens from lower income families and minority teens were significantly more likely to use their phones to go online. Together, these surprising trends suggest a potential narrowing of the digital divide, offering internet access to those without other means of going online. This is an important move, as, in today’s society, internet access is central to active citizenship in ge...

  17. Gender digital divide and online participation: A cross-national analysis

    OpenAIRE

    Chang, Younghoon; Shahzeidi, Mehri; Kim, Hyerin; Park, Myeong-Cheol

    2012-01-01

    To achieve the information society for all, access for all is crucial. However, many countries have reported to have large gender discrepancies in online access and participation. This study empirically verified user perception data and compared the data across countries and genders to determine the differences between countries and genders. The results of surveys in Cambodia, Iran, and Korea verify that each aspect of the digital divide and online participation has a different influence on e...

  18. Bridging “Digital Divide” in Medium and Small-sized Enterprises’Informatization

    OpenAIRE

    Baozhen Chen

    2009-01-01

    Great significance lies in the informatization of medium and small-sized enterprises in that it will convert the economic growth method and improve those enterprises’ competitive abilities at the international market. However, “digital divide” confronted in their informatization must be bridged by reinforcing the support for their informatization process, achieving the goal of informatization step by step, actively promoting “the Enterprises’ Informatization Project” and soundly carrying out ...

  19. Differentiated Products, Divided Industries: Firms and the Politics of Intra-Industry Trade

    OpenAIRE

    Osgood, Iain Guthrie

    2013-01-01

    Which firms support trade liberalization and under what circumstances? The dominant approaches to trade politics ignore two key features of modern international commerce -- firm heterogeneity in export performance and intra-industry trade -- which jointly imply that industries will be divided over bilateral trade liberalization. This dissertation examines the impact of these features on the politics of trade, exploring the preferences of firms, the attitudes of industries, and the motivations...

  20. Household computer and Internet access: The digital divide in a pediatric clinic population

    OpenAIRE

    Carroll, Aaron E.; Rivara, Frederick P; Ebel, Beth; Zimmerman, Frederick J; Christakis, Dimitri A

    2005-01-01

    Past studies have noted a digital divide, or inequality in computer and Internet access related to socioeconomic class. This study sought to measure how many households in a pediatric primary care outpatient clinic had household access to computers and the Internet, and whether this access differed by socio-economic status or other demographic information. We conducted a phone survey of a population-based sample of parents with children ages 0 to 11 years old. Analyses asses...

  1. Contested Normative Cultures. Gendered Perspectives on Religions and the Public/Private Divide.

    DEFF Research Database (Denmark)

    Petersen, Hanne

    2012-01-01

    The article considers religious and secular normative cultures from a gendered perspective focusing on gender and the class and gender privileges linked to the introduction of a public/private divide. It finally discusses issues concerning 'gender display' and gender performance in the 21st century as a field, where 'religion', 'public', 'private' and 'gender' overlap, interact, and possibly take on new forms and new meanings and changes all involved actors.

  2. A Markov Model for Human Resources Supply Forecast Dividing the HR System into Subgroups

    OpenAIRE

    Rachid Belhaj; Mohamed Tkiouat

    2013-01-01

    Modeling the manpower management mainly concerns the prediction of future behavior of employees. The paper presents a predictive model of numbers of employees in a hierarchical dependent-time system of human resources, incorporating subsystems that each contains grades of the same family. The proposed model is motivated by the reality of staff development which confirms that the path evolution of each employee is usually in his family of grades. That is the reason of dividing the system into...

  3. Book review: Divided nations: why global governance is failing and what we can do about it

    OpenAIRE

    Hearson, Martin

    2013-01-01

    "Divided Nations: Why Global Governance is Failing and What We Can Do About It." Ian Goldin. Oxford University Press. March 2013. --- Humanity today faces a number of international challenges which spill over national boundaries: climate change, finance, pandemics, cyber security, and migration. It is becoming increasingly apparent that bodies created to assist in global governance – those such as the UN, the IMF, and the World Bank – are inadequate for the task of managing such risk in th...

  4. The digital divide: Trends in global mobile and broadband Internet access from 2000–2010

    OpenAIRE

    Ronquillo, Charlene; Currie, Leanne

    2012-01-01

    The digital divide is described as the gap between those who do and do not have access to digital information and communications technologies (ICT). ICTs are viewed as an indicator of infrastructure and potential for development, and are a growing platform for health information and services delivery. This study compares the penetration of mobile and broadband Internet technologies by global region from 2000 to 2010. Results illustrate the rapid growth of mobile cellular telephone subscriptio...

  5. Image Segmentation using Enhanced K-means clustering with divide and Conquer Approach

    OpenAIRE

    Babeesh Kumar; Sushila Vikas Maheshkar; Ankur Singh Bist

    2014-01-01

    This paper present image segmentation using Enhanced k-means clustering with divide and conquer approach. First we enhanced the k-means clustering and then segment the image using enhanced approach. K-means is one of the most popular clustering algorithms. The final clustering result of the k-means clustering algorithm greatly depends upon the correctness of the initial centroids, which are selected randomly. Many improvements were already proposed to improve the performance o...

  6. Atoms can be divided into three categories: polar, non-polar and hydrogen atom

    OpenAIRE

    You, Pei-Lin

    2010-01-01

    Since the time of Rutherford 1911) physicists and chemists commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, atoms do not have permanent electric dipole moment (EDM), so that there is no polar atom in nature. In the fact, the idea is untested hypothesis. After ten years of intense research, our experiments showed that atoms can be divided into three categories: polar, non-polar and hydrogen atom. Alkali atoms are al...

  7. Mobile Phones Bridging the Digital Divide for Teens in the US?

    DEFF Research Database (Denmark)

    Brown, Katie; Campbell, Scott; Ling, Richard

    2011-01-01

    In 2009, just 27% of American teens with mobile phones reported using their devices to access the internet. However, teens from lower income families and minority teens were significantly more likely to use their phones to go online. Together, these surprising trends suggest a potential narrowing of the digital divide, offering internet access to those without other means of going online. This is an important move, as, in today’s society, internet access is central to active citizenship in gener...

  8. "Is There a Second Level Divide in Student’s Internet Skills?

    DEFF Research Database (Denmark)

    Dau, Susanne; Purushothaman, Aparna

    2015-01-01

    The concept of a digital divide has moved beyond only physical disparities in technology usage and now also encompasses issues impeding access such as human social, cultural, and psychological barriers that affect the usage of existing available technologies. This paper focuses on students’ insufficient skill levels in making the best use of available Internet technology, discussing students in higher education in scenarios in Denmark and India. The paper emphasizes the reflective and conceptual...

  9. College Students Perception of the Second-Level Digital Divide: An Empirical Analysis

    OpenAIRE

    Fanbin Zeng

    2011-01-01

    The goal of this study was to take a comprehensive measure to the second-level digital divide, along with analyzing the various factors, and finding out the prominent factors. This study comes up with the hypothesis based on three Theoretical framework of Knowledge gap theory, Use and gratifications theory, Self-efficacy and attitude theory. Based on a survey on students of Jinan University (N=302), Multiple linear regression shows that the sensibility factors of Internet use, including the a...

  10. Book review: The price of inequality: how today’s divided society endangers our future.

    OpenAIRE

    Krupa, Joel

    2013-01-01

    "The Price of Inequality: How Today’s Divided Society Endangers Our Future." Joseph Stiglitz. Penguin. April 2013. --- America currently has the most inequality and the least equality of opportunity among the developed countries, writes Nobel Prize-winning economist Joseph E. Stiglitz in The Price of Inequality. While market forces play a role in this stark picture, politics has shaped those market forces. Stiglitz aims to explain how inequality affects and is affected by every aspect of n...

  11. So far Left, we're Right": bridging the cultural divide in California's stem cell controversy

    OpenAIRE

    Higgs, Joan Kathleen

    2010-01-01

    In the United States, the ideological divide between Left/Right, or ‘progressive/conservative’ has been predominantly defined by the abortion issue since its decriminilization in 1973. Feminists who fought that long battle for reproductive rights have been compelled to protect them against political retrenchment. By 2000, human embryonic stem cell research (hESCR) had eclipsed abortion as the point of resistance for right-to-life activists. While aversion to embryo experimentation is not excl...

  12. Identification of an Antigen Localized to an Apparent Septum within Dividing Chlamydiae†

    OpenAIRE

    Brown, W. J.; Rockey, D. D.

    2000-01-01

    The process of chlamydial cell division has not been thoroughly investigated. The lack of detectable peptidoglycan and the absence of an FtsZ homolog within chlamydiae suggest an unusual mechanism for the division process. Our laboratory has identified an antigen (SEP antigen) localized to a ring-like structure at the apparent septum within dividing chlamydial reticulate bodies (RB). Antisera directed against SEP show similar patterns of antigen distribution in Chlamydia trachomatis and Chlam...

  13. Matching frictions and the divide of schooling investment between general and specific skills

    OpenAIRE

    Decreuse, Bruno; Granier, Pierre

    2007-01-01

    This paper examines the impact of labor market frictions and institutions on the divide of schooling investment between general and specific skills. We offer a simple matching model of unemployment in which individuals determine the scope and intensity of their skills. In partial equilibrium, we show that the severity of market frictions distorts the schooling allocation towards more general skills. Then, we endogenize job creation and argue that changes in labor market institutions may well ...

  14. Design of K-Band Substrate Integrated Waveguide Coupler, Circulator and Power Divider

    OpenAIRE

    Bouchra Rahali; Mohammed Feham

    2014-01-01

    Our study concerns the analysis of K-band passive devices using a new technology, substrate integrated waveguide (SIW), by the HFSS code. This technology has been applied successfully to the conception of planar compact components for the microwave and millimeter waves applications. This application focuses on three components: A coupler junction (-3dB) used for routing, dividing and combining the signals in the microwave system. The levels of reflection and isolation below -15dB occupy more ...

  15. Numerical Analysis of Pulsatile Blood Flow in a Stented Human Coronary Artery with a Flow Divider

    OpenAIRE

    Vahab Dehlaghi; Mohammad T. Shadpoor; Siamak Najarian

    2007-01-01

    Shear stress is known to play a central role in restenosis formation and is sensitive to stent geometry. Local flow alterations created by a different stents without and with flow divider were studied to compare the hemodynamic effects of Stent design properties on restenosis in stented human coronary artery. Blood pressure and shear stress values were computed in three different sites, including stented arterial segment, pre-stent and post-stent regions using computational fluid dynamics. Bl...

  16. East-West mortality divide and its potential explanations: proposed research agenda.

    OpenAIRE

    Bobak, M.; Marmot, M

    1996-01-01

    There is a sharp divide in mortality between eastern and western Europe, which has largely developed over the past three decades and is caused mainly by chronic diseases in adulthood. The difference in life expectancy at birth between the best and worst European countries in this respect is more than 10 years for both sexes. The reasons for these differences in mortality are not clear and data currently available permit only speculation. The contributions of medical care and pollution are lik...

  17. A Sub-band Divided Ray Tracing Algorithm Using the DPS Subspace in UWB Indoor Scenarios

    DEFF Research Database (Denmark)

    Gan, Mingming; Xu, Zhinan; Hofer, Markus; Steinböck, Gerhard; Zemen, Thomas

    2015-01-01

    Sub-band divided ray tracing (SDRT) is one technique that has been extensively used to obtain the channel characteristics for ultra-wideband (UWB) radio wave propagation in realistic indoor environments. However, the computational complexity of SDRT scales directly with the number of sub-bands. Although we have proposed a low-complexity SDRT algorithm for one terminal position [1], the computational complexity i s still extremely high when involving multiple mobile terminal positions. Moreover, ...

  18. Arnol'd tongues for a resonant injection-locked frequency divider: analytical and numerical results

    DEFF Research Database (Denmark)

    Bartuccelli, Michele; Deane, Jonathan H.B.; Gentile, Guido; Schilder, Frank

    2010-01-01

    In this paper we consider a resonant injection-locked frequency divider which is of interest in electronics, and we investigate the frequency locking phenomenon when varying the amplitude and frequency of the injected signal. We study both analytically and numerically the structure of the Arnol’d tongues in the frequency–amplitude plane. In particular, we provide exact analytical formulae for the widths of the tongues, which correspond to the plateaux of the devil’s staircase picture. The result...

  19. Poor-Rich Divide in Aravind Adiga’s The White Tiger

    Directory of Open Access Journals (Sweden)

    A.J. Sebastian

    2009-05-01

    Full Text Available Aravind Adiga’s The White Tiger, which was awarded theMan Booker Prize in 2008, is singular in its fictionalized portrayal of the relationship between Balram Halwai and his master Mr Ashok. The story exposes the poor-rich divide that surrounds India in the backdrop of economic prosperity, in the wake of the IT revolution. As Michael Portillo commented the novel “shocked and entertained in equal measure” (Portillo, 2008. Written in the epistolary form, the novel is a seven-part letter to the Chinese Premier, Wen Jiabao, from Balram alias Ashok Sharma, a self-styled ‘Thinking Man / And an entrepreneur’ (TWT, 2008, p. 3. Balram the killer, metamorphoses into his master’s replica after his heinous crime. By crime and cunning, in the name of the social injustice due to existing rich-poor divide in India, Balram rules his entrepreneurial world. This paper attempts to trace the great poor-rich divide manifested through The White Tiger, having dangerous consequences, if unresolved.

  20. Heat control in HVDC resistive divider by PID and NN controllers

    International Nuclear Information System (INIS)

    In this study, a control system is presented that is devised to increase measurement precisions within a prototype high voltage DC resistive divider (HVDC-RD). Since one of the major sources of measurement errors in such devices is the self heating effect, a system controlling the temperature within the high voltage DC resistive divider is devised so that suitable and stable temperature conditions are maintained that, in return, will decrease the measurement errors. The resistive divider system is cooled by oil, and PID and neural network (NN) controllers try to keep the temperature within the prescribed limits. The system to be controlled exhibits a nonlinear character, and therefore, a control approach based on NN controllers is proposed. Thus, a system that can fulfill the various requirements dictated by the designer is constructed. The performance of the NN controller is compared with that of the PID controller developed for the same purpose, and the values of the performance indices indicate the superiority of the NN controller over that of the classical PID controller

  1. Uranium and radon in the ground water

    International Nuclear Information System (INIS)

    The uranium (U) and the radon (Rn) concentrations in the Finnish groundwaters were studied and the results of the investigation are discussed in this article. The investigation comprises more than 10 000 water samples taken from drilled wells all over the country. The waters were divided into different groups by dominant rock type to establish the influence of the geological environment of the water

  2. Ground-water travel time

    International Nuclear Information System (INIS)

    The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Travel Time Subgroup are presented

  3. Regional ground-water system

    International Nuclear Information System (INIS)

    The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Regime Subgroup are presented

  4. Mapping and explaining the use of the left-right divide

    Scientific Electronic Library Online (English)

    André, Freire; Kats, Kivistik.

    Full Text Available This study is about mapping and explaining the use of the Left-Right divide across 14 countries from 5 Continents and relies on the richness of the post electoral mass surveys from the Comparative National Election Project: 14 countries and 18 elections spread over 5 continents. The paper shows not [...] only how extensively the LR divide is used in these 14 countries, but also explains variation across both individuals and countries in terms of the factors determining LR recognition and use. Overall, it is shown that, although seen world-wide, the LR divide (both for self-placement and party placement) is more present in long consolidated and middle-aged democracies and countries with freer media systems than in new democracies and societies with less free media systems. In the case of parties LR placement, party size also counts: larger parties are more easily placed. Additionally, we also show that LR recognition is more socially and politically determined in long consolidated and middle-aged democracies and in countries with more freedom of the press than in new democracies and in systems with less free media system. These findings add to the existing knowledge about these topics because previous studies were either country/Continent specific, or, if global in nature, never invested in explaining individual and system variation across 14 from 5 Continents. Besides, these findings mean that in the long term probably the new democracies will converge with the long consolidated or middle-aged ones, but this is an empirical question to be researched in future studies.

  5. A Divide-and-Conquer Method for Scalable Robust Multitask Learning.

    Science.gov (United States)

    Pan, Yan; Xia, Rongkai; Yin, Jian; Liu, Ning

    2015-12-01

    Multitask learning (MTL) aims at improving the generalization performance of multiple tasks by exploiting the shared factors among them. An important line of research in the MTL is the robust MTL (RMTL) methods, which use trace-norm regularization to capture task relatedness via a low-rank structure. The existing algorithms for the RMTL optimization problems rely on the accelerated proximal gradient (APG) scheme that needs repeated full singular value decomposition (SVD) operations. However, the time complexity of a full SVD is O(min(md(2),m(2)d)) for an RMTL problem with m tasks and d features, which becomes unaffordable in real-world MTL applications that often have a large number of tasks and high-dimensional features. In this paper, we propose a scalable solution for large-scale RMTL, with either the least squares loss or the squared hinge loss, by a divide-and-conquer method. The proposed method divides the original RMTL problem into several size-reduced subproblems, solves these cheaper subproblems in parallel by any base algorithm (e.g., APG) for RMTL, and then combines the results to obtain the final solution. Our theoretical analysis indicates that, with high probability, the recovery errors of the proposed divide-and-conquer algorithm are bounded by those of the base algorithm. Furthermore, in order to solve the subproblems with the least squares loss or the squared hinge loss, we propose two efficient base algorithms based on the linearized alternating direction method, respectively. Experimental results demonstrate that, with little loss of accuracy, our method is substantially faster than the state-of-the-art APG algorithms for RMTL. PMID:25775500

  6. Gold mineralisation near the Main Divide, upper Wilberforce valley, Southern Alps, New Zealand

    International Nuclear Information System (INIS)

    Veins up to 8 m wide fill extensional fractures in Torlesse Terrane metasediments near the Main Divide in the upper Wilberforce valley, Canterbury, New Zealand. The upper Wilberforce veins are part of a prominent 40 km long, NNE-trending swarm of gold-bearing veins formed across the Main Divide during the Late Cenozoic rise of the Southern Alps. The veins occur within, and near, a prominent set of faults which constitute the Main Divide Fault Zone. The veins are irregular in shape due to contrasting host rock properties, and have been only weakly sheared and deformed. Veins cut across greywacke beds and follow irregularly along argillite beds, on the 1-10 m scale. Quartz dominates vein mineralogy, but albite forms up to 45% of some veins, and minor chlorite, pyrite, arsenopyrite, chalcopyrite, and gold occur sporadically, especially in breccias near vein margins. Fluid inclusions in vein quartz homogenise at 180-253 degrees C, and arsenopyrite composition (28.3-30.8 at.% As) suggest formation temperatures of 250-350 degrees C. Elevated arsenic levels (up to 200 ppm above a background of 10 ppm) in some host greywackes and argellites suggest that hydrothermal activity pervaded host rocks as well as forming veins, but there is no textural evidence for this fluid flow. Late-stage carbonates in faults adjacent to the quartz veins, but which postdate the quartz veins, have ?18O ranging from 11.1 to 25.6 per thousand, and ?13C ranging from -12.5 to -1.1 per thousand. These carbonates were deposited by a mixture of meteoric and crustally isotopically exchanged fluid as a shallow-level manifestation of the same hydrothermal system which deposited the quartz veins. The upper Wilberforce veins structurally and mineralogically resemble some Late Cenozoic gold-bearing vein systems in the Mt Cook area, 100 km to the southwest along the Southern Alps. (author). 52 refs., 9 figs., 3 tabs

  7. eGY-Africa: addressing the digital divide for science in Africa

    Science.gov (United States)

    Baki, Paul; Nguno, Anna; Barton, Charles; Amaeshi, Larry; Tenthani, Chifundo; Petitdidier, Monique; Cottrell, Les

    2013-04-01

    Adoption of information and communication technologies and access to the Internet is expanding in Africa, but because of the rapid growth elsewhere, a Digital Divide between Africa and the rest of the world exists. In many sub-Saharan African countries, education and research sector suffers some of the worst deficiencies in access to the Internet, despite progress in the development of NRENs - National Research and Education (cyber) Networks. By contrast, it is widely acknowledged in policy statements from the African Union, the UN, and others that strength in this very sector provides the key to meeting and sustaining Millennium Development Goals. Developed countries with effective cyber-capabilities proclaim the benefits to rich and poor alike arising from the Information Revolution. This is still a dream for many scientists in African institutions. As the world of science becomes increasingly Internet-dependent, so they become increasingly isolated. eGY-Africa is a bottom-up initiative by African scientists and their collaborators to try to reduce this digital divide by a campaign of advocacy for better institutional facilities. Four approaches are being taken. The present status of Internet services, problems, and plans are being mapped via a combination of direct measurement of Internet performance (the PingER Project) and a questionnaire-based survey. Information is being gathered on policy statements and initiatives aimed at reducing the digital divide, which can be used for arguing the case for better Internet facilities. Groups of concerned scientists are being formed at the national, regional levels in Africa, building on existing networks as much as possible. Opinion in the international science community is being mobilized. Finally, and perhaps most important of all, eGY-Africa is seeking to engage with the many other programs, initiatives, and bodies that share the goal of reducing the digital divide - either as a direct policy objective, or indirectly as a means to an end, such as the development of an indigenous capability in science and technology for national development. The expectation is that informed opinion from the scientific community at the institutional, national, and international levels can be used to influence the decision makers and donors who are in a position to deliver better Internet capabilities. eGYAfrica workshops have been held approximately bi annually, the last of which was in Nairobi Kenya.

  8. Comparing Perception of Stroop Stimuli in Focused versus Divided Attention Paradigms: Evidence for Dramatic Processing Differences

    OpenAIRE

    Eidels, Ami; Townsend, James T.; Algom, Daniel

    2009-01-01

    A huge set of focused attention experiments show that when presented with color words printed in color, observers report the ink color faster if the carrier word is the name of the color rather than the name of an alternative color, the Stroop effect. There is also a large number (although not so numerous as the Stroop task) of so-called “redundant targets studies” that are based on divided attention instructions. These almost always indicate that observers report the presence of a visual tar...

  9. Divide and Merge Classification for High Dimensional Multi-Class Datasets

    Directory of Open Access Journals (Sweden)

    Sejong Oh

    2015-01-01

    Full Text Available If a dataset has multiple classes and huge features like microarray data, classification accuracy may be low, even though feature selections are applied to reduce the dimensions of the dataset. Improvement of classification accuracy for the dataset is a challenging task. We propose an efficient classification method based on the "Divide-and-Merge" approach for high dimensional multi-class datasets. In the proposed method, we extracted different feature subsets for each class in an original dataset and generate new datasets. Unknown sample Si is classified into the new datasets and the results are merged for a final decision of the class label.

  10. Arnol'd tongues for a resonant injection-locked frequency divider: analytical and numerical results

    DEFF Research Database (Denmark)

    Bartuccelli, Michele; Deane, Jonathan H.B.

    2010-01-01

    In this paper we consider a resonant injection-locked frequency divider which is of interest in electronics, and we investigate the frequency locking phenomenon when varying the amplitude and frequency of the injected signal. We study both analytically and numerically the structure of the Arnol’d tongues in the frequency–amplitude plane. In particular, we provide exact analytical formulae for the widths of the tongues, which correspond to the plateaux of the devil’s staircase picture. The results account for numerical and experimental findings presented in the literature for special driving terms and, additionally, extend the analysis to a more general setting.

  11. Divide by 4 the emissions: the Negatep scenario; Diviser par 4 nos rejets: le scenario Negatep

    Energy Technology Data Exchange (ETDEWEB)

    Acket, C.; Bacher, P

    2007-01-15

    The Negatep scenario is proposed in the framework of the french energy policy, aiming to divide by 4 the CO{sub 2} emissions for 2050. After an evaluation of the today situation concerning the energy consumption and needs, the scenario proposes some ways of energy conservation in different sectors, other energy sources in place of the fossil fuels, the energy needs by sectors. The last part of the document provides the main consumption posts, the CO{sub 2} releases and the approach. (A.L.B.)

  12. eGY-Africa: Addressing the Digital Divide for Science in Africa

    Energy Technology Data Exchange (ETDEWEB)

    Barton, C.E.; /Australian Natl. U., Canberra; Amory-Mazaudier, C.; /Lab.Phys.Plasmas, Saint Maur des Fosses; Barry, B.; /Assoc.African Univ., Accra; Chukwuma; /Olabisi Onabanjo U.; Cottrell, R.L.; /SLAC; Kalim, U.; /Pakistan Natl. U.; Mebrahtu, A.; /Mekelle U.; Petitdidier, M.; /Lab. d' Atmos., Velizy; Rabiu, B.; /Federal Tech. U., Akure; Reeves, C.; /Earthworks bv, Delft

    2010-06-16

    Adoption of information and communication technologies and access to the Internet is expanding in Africa, but because of the rapid growth elsewhere, a Digital Divide between Africa and the rest of the world exists, and the gap is growing. In many sub-Saharan African countries, education and research sector suffers some of the worst deficiencies in access to the Internet, despite progress in development of NRENs - National Research and Education (cyber) Networks. By contrast, it is widely acknowledged in policy statements from the African Union, the UN, and others that strength in this very sector provides the key to meeting and sustaining Millennium Development Goals. Developed countries with effective cyber-capabilities proclaim the benefits to rich and poor alike arising from the Information Revolution. This is but a dream for many scientists in African institutions. As the world of science becomes increasingly Internet-dependent, so they become increasingly isolated. eGY-Africa is a bottom-up initiative by African scientists and their collaborators to try to reduce this Digital Divide by a campaign of advocacy for better institutional facilities. Four approaches are being taken. The present status of Internet services, problems, and plans are being mapped via a combination of direct measurement of Internet performance (the PingER Project) and a questionnaire-based survey. Information is being gathered on policy statements and initiatives aimed at reducing the Digital Divide, which can be used for arguing the case for better Internet facilities. Groups of concerned scientists are being formed at the national, regional levels in Africa, building on existing networks as much as possible. Opinion in the international science community is being mobilized. Finally, and perhaps most important of all, eGY-Africa is seeking to engage with the many other programs, initiatives, and bodies that share the goal of reducing the Digital Divide - either as a direct policy objective, or indirectly as a means to an end, such as the development of an indigenous capability in science and technology for national development. The expectation is that informed opinion from the scientific community at the institutional, national, and international levels can be used to influence the decision makers and donors who are in a position to deliver better Internet capabilities.

  13. Confidence intervals for the critical value in the divide and color model

    OpenAIRE

    Bálint, András; Beffara, Vincent; Tassion, Vincent

    2013-01-01

    We obtain confidence intervals for the location of the percolation phase transition in H\\"aggstr\\"om's divide and color model on the square lattice $\\mathbb{Z}^2$ and the hexagonal lattice $\\mathbb{H}$. The resulting probabilistic bounds are much tighter than the best deterministic bounds up to date; they give a clear picture of the behavior of the DaC models on $\\mathbb{Z}^2$ and $\\mathbb{H}$ and enable a comparison with the triangular lattice $\\mathbb{T}$. In particular, o...

  14. On the origin of 'dividing lines' for late-type giants and supergiants

    Science.gov (United States)

    Rosner, R.; Musielak, Z. E.; Cattaneo, F.; Moore, R. L.; Suess, S. T.

    1995-01-01

    We show how a change in the nature of the stellar dyanmo can lead to a transition in the topological character of stellar magnetic fields of evolved stars, from being mainly closed on the blueward side of the giant tracks in the Hertzsprung-Russell (H-R) diagram to being mainly open on their redward side. If such a topological transition occurs, then these stars naturally segregate into two classes: those having hot coronae on the blueward side, and those having massive cool winds on the redward side, thus leading naturally to the so-called dividing lines.

  15. A CRITICAL EVALUATION OF INDIAN GOVERNMENT’S STRATEGIES TO BRIDGE DIGITAL DIVIDE

    OpenAIRE

    Nityesh BHATT

    2006-01-01

    Emergence of Information and Communication Technology (ICT) has been a landmark for India. In one way, this sunshine sector has been instrumental in the economic growth of country and has glorified its image in the whole world but on the other end, it has also created a digital divide in our society. BBC's Jill McGivering reports that the IT revolution is only changing some lives in the world's largest democracy. (Bagla,2005) A small section of society is harnessing it fully for their advanta...

  16. Active microwave absorber with the dual-ability of dividable modulation in absorbing intensity and frequency

    Directory of Open Access Journals (Sweden)

    Xiaoyu Wu

    2013-02-01

    Full Text Available We present the design, fabrication and experimental demonstration of an electrically active absorber at microwave frequency. Unlike those proposed before, simulation and experiment data present that its working frequency and absorbing intensity can be both but separately controlled. The electromagnetic coupling analysis reveals that the feature arises from the dividable frequency and amplitude modulation on an active magnetic resonator controlled by varactor and pin diodes. Such separable modulating behaviors are further confirmed by the equivalent LC circuit model. It is believed that this will be an important step towards smart application of active absorber.

  17. Radioanalysis of water

    International Nuclear Information System (INIS)

    This chapter describes radioanalytical techniques and extensive results on trace element analysis in water. For practical analytical reasons, it is divided into sea, rain, fresh surface and waste water. A rapid and quantitative preconcentration procedure for sea and fresh surface water is presented. The use of some scavenging procedure like that with active carbon is preferable. Gamma ray spectra of carbon samples for different pH and added reagents are given. The data presented includes those of uranium, thorium and radium. (G.J.P.)

  18. Design of a water distribution system

    OpenAIRE

    Mavroudis, George

    1989-01-01

    The design of a water distribution system is a very useful project for all who deel with it. . For better explanation of the several steps followed until water appears in a community, this project was divided in to chapters. The first chapter refers to water its importance to all humanity and its uses. Chapter 2 gives a very briefly explanation about water quality - storage and treatment, necessary knowledge for a good Water Distribution System. All necessary des...

  19. Effects of nonlinear rheology, temperature and anisotropy on the relationship between age and depth at ice divides

    Directory of Open Access Journals (Sweden)

    C. Martín

    2012-06-01

    Full Text Available Ice flow in divide areas is strongly anisotropic. The evolution of ice fabric, from the onset of divide flow towards steady-state with a fully-developed fabric, has been shown to profoundly affect both the stratigraphy and surface topography of ice divides. Here, we investigate the effects of ice flow on the age-versus-depth relationship at ice divides by using a full Stokes thermomechanical model with a non-linear anisotropic constitutive relation between stress and strain rates. We compare our results with analytical approximations commonly employed in age–depth predictions such as the Dansgaard and Lliboutry approximations. We show that these approximations systematically underestimate the age of ice at fully-developed divides by as much as one order of magnitude. We also show that divides with fully-developed fabric are ideal locations for ice-core extraction because ice under them can be up to one order of magnitude older than ice at the same depth at the flanks. In addition, these divides have a distinctive morphological structure that allows them to be clearly identified from satellite imagery or ground-penetrating radar data. Our results are particularly relevant in coastal areas of Antarctica where divides with fully-developed ice fabric are widespread.

  20. Structure and fluid migration in a Late Cenozoic duplex system forming the Main Divide in the central Southern Alps, New Zealand

    International Nuclear Information System (INIS)

    The Alpine Schist immediately west of the Main Divide of the Southern Alps is a west-dipping duplex system consisting of an imbricated stack of rock slabs, each c. 250-1000 m thick. The imbricated stack has low grade, little deformed pumpellyite-actinolite facies semischists at the base, overlain by progressively higher grade and more deformed schists. The structurally highest slab mapped consists of multiply-deformed biotite zone schist. The duplex lies on the hanging wall of the northwest-dipping Main Divide Fault Zone, which separates semischist from structurally underlying greywacke. Rock slabs are internally disrupted by faults subparallel to layering, and consist of lozenge-shaped blacks of 10-100 m. Fault zones separating rock slabs consist of 18O(SMOW) between 11.4 and 26.1 per thousand, and ?13C(PDB) between -.6 and -11.4 per thousand. Calculated isotopic ratios for the mineralising fluids show little evidence for meteoric origin. The fluid may be meteoric water which has undergone isotopic exchange with host rocks, metamorphic water, or a mixture of these, and mineralisation occurred during rise of the fluids from depth. (author). 56 refs., 12 figs., 3 tabs

  1. Discovery of Opinion Leader Community Via Multilayer Structure based Time-dividing Approach

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2013-07-01

    Full Text Available With the advent of web 3.0, social network has become an important way to disclosure and spread the public sentiment. Opinion leaders play an important role in leading the direction of the public opinion. In this paper, due to the structure of the community in the network, we extracted the community by replies of each post in BBS, and we came up with an opinion leader community mining method based on level structure. In this way the communities each other have a better overlap result. Thus, communities can have more relations. Then, we analyzed the revolution of the communities after we got the structure of the opinion leader communities and we put forward a time-dividing method, and divided the whole communities into different pieces based on the character of the post and the duration of the time and we came up with the suitable measurement parameter to get the evolution result of the communities. Finally, experiments prove the efficiency of the opinion leader community mining method and we summarize the properties of the opinion leader community in revolution.

  2. Energy-Saving Coil Excitation of Electromagnetic Levitation System Using Divided Iron Core Type Hybrid Magnet

    Science.gov (United States)

    Kakinoki, Toshio; Yamaguchi, Hitoshi; Sinohara, Katsuji

    Energy saving control is desirable for magnetically levitated (MAGLEV) vehicles. Hybrid magnets controlled with zero power control system was able to reduce the exciting power. But such a conventional system needed to feed bipolar current and then the excitation system was complicated. To achieve a simple excitation system, a hybrid magnet with permanent magnets and divided cores was made. The magnet was a salient-pole type magnet and the poles were placed in two rows. Each pole of the iron cores was equipped with a coil to control both levitation force and lateral damping force. The coils of one side of the divided core were excited with a direct current driver so as to produce the same polarity as the permanent magnet and the others were excited the opposite polarity. The two sets of the coils were excited with direct current drivers each of which had one IGBT. The system needed only two IGBTs per magnet while the conventional zero power systems needed four IGBTs per magnet. According to our test results, the energy consumption was very small and the levitation part was able to start levitating from both upper and lower touch-down positions. In this paper, the characteristics of the proposed excitation system are shown.

  3. The influence of thematic congruency, typicality and divided attention on memory for radio advertisements.

    Science.gov (United States)

    Martín-Luengo, Beatriz; Luna, Karlos; Migueles, Malen

    2014-01-01

    We examined the effects of the thematic congruence between ads and the programme in which they are embedded. We also studied the typicality of the to-be-remembered information (high- and low-typicality elements), and the effect of divided attention in the memory for radio ad contents. Participants listened to four radio programmes with thematically congruent and incongruent ads embedded, and completed a true/false recognition test indicating the level of confidence in their answer. Half of the sample performed an additional task (divided attention group) while listening to the radio excerpts. In general, recognition memory was better for incongruent ads and low-typicality statements. Confidence in hits was higher in the undivided attention group, although there were no differences in performance. Our results suggest that the widespread idea of embedding ads into thematic-congruent programmes negatively affects memory for ads. In addition, low-typicality features that are usually highlighted by advertisers were better remembered than typical contents. Finally, metamemory evaluations were influenced by the inference that memory should be worse if we do several things at the same time. PMID:23947823

  4. Multivesicular bodies differentiate exclusively in nutritive fast-dividing cells in Marcetia taxifolia galls.

    Science.gov (United States)

    Ferreira, Bruno G; Carneiro, Renê G S; Isaias, Rosy M S

    2015-09-01

    Marcetia taxifolia (A. St.-Hil.) DC. hosts two gall morphotypes, a pistil-shaped gall induced by a Cecidomyiidae (Diptera) and a fusiform stem gall induced by a Lepidoptera. The cytological study of these galls aimed to answer how the difference in nutritive tissues of Diptera and Lepidoptera galls could be explained on cytological basis. The nutritive tissues of lepidopteran galls have a fast-dividing cell zone, the storage nutritive tissue, which replaces the cells of the typical nutritive tissue, where the larvae feed. The differentiation of multivesicular bodies in the plasma membrane occurred exclusively in these fast-dividing cells of the lepidopteran galls, evidencing the meristematic condition of such tissue. The accumulation of reactive oxygen species (ROS) analyzed in situ in the nutritive cells is not sufficient to induce programmed cell death (PCD), as the cells of M. taxifolia have plastoglobules and accumulate polyphenols and terpenoids, which are diagnostic defenses against oxidative stress. The two taxa of galling insects have different nutritional requirements, thus inducing specific cytoplasm-enriched cells on their nutritive tissues. PMID:25613290

  5. Controlling hollow relativistic electron beam orbits with an inductive current divider

    International Nuclear Information System (INIS)

    A passive method for controlling the trajectory of an intense, hollow electron beam is proposed using a vacuum structure that inductively splits the beam's return current. A central post carries a portion of the return current (I1), while the outer conductor carries the remainder (I2). An envelope equation appropriate for a hollow electron beam is derived and applied to the current divider. The force on the beam trajectory is shown to be proportional to (I2-I1), while the average force on the envelope (the beam width) is proportional to the beam current Ib?=?(I2?+?I1). The values of I1 and I2 depend on the inductances in the return-current path geometries. Proper choice of the return-current geometries determines these inductances and offers control over the beam trajectory. Solutions using realistic beam parameters show that, for appropriate choices of the return-current-path geometry, the inductive current divider can produce a beam that is both pinched and straightened so that it approaches a target at near-normal incidence with a beam diameter that is on the order of a few mm

  6. Information Resources Column: "The Digital Divide: How Wide and How Deep?

    Directory of Open Access Journals (Sweden)

    Schloman, B

    2004-05-01

    Full Text Available The complexity of the issues that make up the digital divide problem is better understood today. It is no longer sufficient to see it simply as a disparity of access to computer technology. Rather, there is recognition that having meaningful support for using the technology is also an essential ingredient for getting online. The digital divide is a global problem, but even in the technology rich United States the situation is troubling. Recent studies have shown that within the United States, public libraries play a key role in helping the digitally disadvantaged get connected to the Internet and learn how to use it to serve their needs. As more individuals are connected online, those who are not, however, are increasingly in danger for becoming more marginalized within society. Health care professionals need to be aware that they may well be working with individuals who are increasingly outside of the mainstream of the digital revolution and who cannot take advantage of Internet resources that could positively impact their health.

  7. Metacognition of multitasking: How well do we predict the costs of divided attention?

    Science.gov (United States)

    Finley, Jason R; Benjamin, Aaron S; McCarley, Jason S

    2014-06-01

    Risky multitasking, such as texting while driving, may occur because people misestimate the costs of divided attention. In two experiments, participants performed a computerized visual-manual tracking task in which they attempted to keep a mouse cursor within a small target that moved erratically around a circular track. They then separately performed an auditory n-back task. After practicing both tasks separately, participants received feedback on their single-task tracking performance and predicted their dual-task tracking performance before finally performing the 2 tasks simultaneously. Most participants correctly predicted reductions in tracking performance under dual-task conditions, with a majority overestimating the costs of dual-tasking. However, the between-subjects correlation between predicted and actual performance decrements was near 0. This combination of results suggests that people do anticipate costs of multitasking, but have little metacognitive insight on the extent to which they are personally vulnerable to the risks of divided attention, relative to other people. PMID:24490818

  8. Global digital divide: determinants of cross-country ICT development with special reference to Southeast Asia

    Directory of Open Access Journals (Sweden)

    Debbra Toria Nipo

    2014-09-01

    Full Text Available Information and communication technology (ICT tools are regarded as imperative not only for enabling the economy to grow at a healthy rate, but also for elevating the socioeconomic conditions and standards of the society. In concurrence with the widespread diffusion of ICT, lies the phenomenon called digital divide – a complex issue pertaining to unequal access, use and applications of ICT among countries and peoples. This paper attempts to measure the contribution of conventional factors such as affordability, infrastructure, trade openness and urbanization, with added emphasis on the role of financial development in explaining cross-country development of ICT among Southeast Asian countries. Using panel data for 4 countries for the period 1994 – 2011, findings of this study revealed that GDP is the most significant determinant in explaining digital divide – consistent with findings from previous research efforts. Financial development also appear significant in most models adopted in all three ICT tools, implying the need for these countries to improve their financial markets to avoid falling further behind in promoting a digitally inclusive society.

  9. Understanding the divide between the theory and practice of organisational change

    Directory of Open Access Journals (Sweden)

    Julien Pollack

    2015-07-01

    Full Text Available This paper reviews the different ways that academics and practitioners write about and discuss change management, to develop an understanding of whether there is a divide between the theory and practice of change management. This research used scientometric research techniques to compare three corpora: one based on the most cited research in the general management literature on change management; one based on the most cited research in specialist change management journals; and one based on interviews with practising change managers. It was found that the general management literature emphasised an abstract understanding of knowledge management and the learning organisation, while the change management literature focused more on issues associated with value, culture and social identity. The practitioners emphasised issues at the individual, project and team levels, the need for the effective use of targeted communication to achieve organisational change objectives, and the value of rapidly identifying key drivers in a new context. This research found significant differences between these three corpora, which lends support to other researchers’ claims of a divide between theory and practice in change management.

  10. Ensemble Kalman Filtering with a Divided State-Space Strategy for Coupled Data Assimilation Problems

    KAUST Repository

    Luo, Xiaodong

    2014-12-01

    This study considers the data assimilation problem in coupled systems, which consists of two components (subsystems) interacting with each other through certain coupling terms. A straightforward way to tackle the assimilation problem in such systems is to concatenate the states of the subsystems into one augmented state vector, so that a standard ensemble Kalman filter (EnKF) can be directly applied. This work presents a divided state-space estimation strategy, in which data assimilation is carried out with respect to each individual subsystem, involving quantities from the subsystem itself and correlated quantities from other coupled subsystems. On top of the divided state-space estimation strategy, the authors also consider the possibility of running the subsystems separately. Combining these two ideas, a few variants of the EnKF are derived. The introduction of these variants is mainly inspired by the current status and challenges in coupled data assimilation problems and thus might be of interest from a practical point of view. Numerical experiments with a multiscale Lorenz 96 model are conducted to evaluate the performance of these variants against that of the conventional EnKF. In addition, specific for coupled data assimilation problems, two prototypes of extensions of the presented methods are also developed in order to achieve a trade-offbetween efficiency and accuracy.

  11. Application of partially diabatic divided wall column to floating liquefied natural gas plant

    International Nuclear Information System (INIS)

    The offshore operation of chemical plant requires the compactness of process equipments due to its harsh environment. A DWC (divided wall column), a compact ternary separator, is a good candidate for distillation process in the offshore operation. In this study the DWC is applied to the offshore FLNG (floating liquefied natural gas) plant, but high utility cost is required in the application because of the large difference of boiling points among feed components. A partially diabatic DWC is proposed for the reduction of the operating cost here, and its design procedure is presented along with performance and economic evaluations and the examination of thermodynamic efficiency as well. The heating duty of the proposed DWC including tray heat transfer is 35% less than that of the conventional system, and the cooling duty is 18% less. The evaluation indicates that some 16% less utility cost is used in the DWC compared with the conventional system, though 7% more investment is required. The exergy loss is reduced by 12%, and the thermodynamic efficiency is improved by 3.3 percentage point over the conventional system. - Highlights: • Diabatic divided wall column for FLNG (floating liquefied natural gas) plant. • Compact column for offshore operation. • 35% less heating duty required. • 16% lower utility necessary. • Exergy loss reduced by 12%

  12. Labor market conditions and violent crime across the metro-nonmetro divide.

    Science.gov (United States)

    Lee, Matthew R; Slack, Tim

    2008-09-01

    This analysis extends prior research on labor market conditions and violent crime. Specifically, we elaborate on research demonstrating a link between poor labor market conditions and violence by directly measuring the associations between secondary sector work, low hour work, low pay work, and levels of violence across the metro-nonmetro divide. The results demonstrate that low paying work tends to be more similar to other forms of social disadvantage such as poverty and unemployment. In contrast, secondary sector work and low hour work are empirically distinct constructs. Consistent with prior research, multivariate analyses indicate that the pernicious effect of secondary sector work is relatively constant across metro and nonmetro areas. However, contrary to the logic articulated in previous studies, we find that an index of low hour and seasonal employment is actually associated with lower violent crime rates across the metro-nonmetro divide. This finding is consonant with the assertion that the availability of low hour and seasonal employment--work that is often viewed as less than optimal--provides downward pressure on crime rates because it structures ecological behavior patterns and enhances attachments to institutions cultivating conventional behavior. PMID:19086114

  13. Ensemble Kalman filtering with a divided state-space strategy for coupled data assimilation problems

    CERN Document Server

    Luo, Xiaodong

    2014-01-01

    This study considers the data assimilation problem in coupled systems, which consists of two components (sub-systems) interacting with each other through certain coupling terms. A straightforward way to tackle the assimilation problem in such systems is to concatenate the states of the sub-systems into one augmented state vector, so that a standard ensemble Kalman filter (EnKF) can be directly applied. In this work we present a divided state-space estimation strategy, in which data assimilation is carried out with respect to each individual sub-system, involving quantities from the sub-system itself and correlated quantities from other coupled sub-systems. On top of the divided state-space estimation strategy, we also consider the possibility to run the sub-systems separately. Combining these two ideas, a few variants of the EnKF are derived. The introduction of these variants is mainly inspired by the current status and challenges in coupled data assimilation problems, and thus might be of interest from a pr...

  14. Controlling hollow relativistic electron beam orbits with an inductive current divider

    Energy Technology Data Exchange (ETDEWEB)

    Swanekamp, S. B.; Richardson, A. S.; Angus, J. R.; Cooperstein, G.; Hinshelwood, D. D.; Ottinger, P. F.; Rittersdorf, I. M.; Schumer, J. W.; Weber, B. V.; Zier, J. C. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2015-02-15

    A passive method for controlling the trajectory of an intense, hollow electron beam is proposed using a vacuum structure that inductively splits the beam's return current. A central post carries a portion of the return current (I{sub 1}), while the outer conductor carries the remainder (I{sub 2}). An envelope equation appropriate for a hollow electron beam is derived and applied to the current divider. The force on the beam trajectory is shown to be proportional to (I{sub 2}-I{sub 1}), while the average force on the envelope (the beam width) is proportional to the beam current I{sub b}?=?(I{sub 2}?+?I{sub 1}). The values of I{sub 1} and I{sub 2} depend on the inductances in the return-current path geometries. Proper choice of the return-current geometries determines these inductances and offers control over the beam trajectory. Solutions using realistic beam parameters show that, for appropriate choices of the return-current-path geometry, the inductive current divider can produce a beam that is both pinched and straightened so that it approaches a target at near-normal incidence with a beam diameter that is on the order of a few mm.

  15. How 18- and 24-month-old peers divide resources among themselves.

    Science.gov (United States)

    Ulber, Julia; Hamann, Katharina; Tomasello, Michael

    2015-12-01

    Young children are often considered "selfish" with resources because they are reluctant to give up things already in their possession (e.g., as in dictator games). In the current two studies, we presented pairs of 18- and 24-month-old toddlers with various situations involving resources that no one possessed ahead of time. We observed very few instances of individuals attempting to monopolize the resources; rather, the pair peaceably divided them such that each child got something. Equal divisions--even involving one child sacrificing his or her own resources to establish equality-were especially pronounced when children were acting together jointly even in the absence of active collaboration. Children's divisions were also influenced by cues to ownership such as a spatial pre-division of resources and resources marked by color (and originally spatially associated with one individual). These results suggest that young children are not selfish, but instead rather generous, with resources when they are dividing them among themselves. PMID:26283235

  16. Dividing by four CO2 releases due to energy: the Negatep scenario

    International Nuclear Information System (INIS)

    The Negatep scenario aims at dividing CO2 releases by 4, which means, more or less, dividing the consumption of fossil energies by the same factor, in order to comply with the French 2005 energy act. After a description of the situation in 2006, of trends, and a recall of the objectives defined by the 'Grenelle de l'Environnement' regarding energy savings and renewable energies, the authors show that reaching such a reduction requires to: decrease to nearly zero oil and gas in the residential and tertiary sectors, reduce significantly the use of oil in the transport sector, reduce significantly the use of fossil fuels in industry, increase massively the share of electricity in the energy mix, maintain the share of nuclear in the electricity generation and, as long as the storage of electricity is not developed, limit the share of intermittent energies to a level compatible with that of gas turbines. The study shows that the proposed measures can fulfill the objectives for 2020 proposed by the 'Grenelle de l'Environnement'

  17. Design of K-Band Substrate Integrated Waveguide Coupler, Circulator and Power Divider

    Directory of Open Access Journals (Sweden)

    Bouchra Rahali

    2014-01-01

    Full Text Available Our study concerns the analysis of K-band passive devices using a new technology, substrate integrated waveguide (SIW, by the HFSS code. This technology has been applied successfully to the conception of planar compact components for the microwave and millimeter waves applications. This application focuses on three components: A coupler junction (-3dB used for routing, dividing and combining the signals in the microwave system. The levels of reflection and isolation below -15dB occupy more than 26.43% of the bandwidth, the insertion loss S21 and coupling S31 fluctuate between -3.24dB and -3.78dB, respectively. The SIW ferrite junction circulator has potential applications in integrated communication and radar systems. Its frequency response shows reflection losses below -15 dB in more than 21.75% of the bandwidth, an insertion loss about -0.65 dB, while the maximum of the isolation is -38.11dB. The T-junction SIW power divider (-3dB indicates that levels of reflection below -15dB occupy more than 26.32% of the bandwidth. The transmission coefficients S21 and S31 are around -3.54dB, showing equal division of the power injected into port 1. In this paper, design considerations and results are discussed and presented.

  18. Decolorization and mineralization of Orange G azo dye solutions by anodic oxidation with a boron-doped diamond anode in divided and undivided tank reactors

    International Nuclear Information System (INIS)

    Highlights: • Acidic Orange G azo dye solutions completely degraded by anodic oxidation with BDD. • Quicker decolorization and mineralization in a divided than an undivided cell. • Similar time needed for total decolorization and disappearance of Orange G. • Maleic, tartronic, acetic, formic, oxalic and oxamic acids as generated carboxylic acids. • Ammonium and sulfate as main inorganic ions released during dye mineralization. - Abstract: The decolorization and mineralization of 100 cm3 of 0.52-6.34 mmol dm?3 Orange G azo dye solutions at pH 3.0 and current density between 33.3 and 150 mA cm?2 have been studied by anodic oxidation (AO) using a divided or undivided tank reactor with a boron-doped diamond (BDD) anode and a stainless steel cathode. In both systems, organics were destroyed by hydroxyl radicals generated at the BDD anode from water oxidation. Solutions with 0.52 mmol dm?3 of the dye were completely decolorized in both cells, more rapidly at greater current density. The divided cell always gave faster decolorization than the undivided one. Overall mineralization in the divided tank reactor was attained in less than 330 min operating at current densities ? 66.7 mA cm?2, whereas in the undivided cell, this was feasible at times as long as 420 min for 150 mA cm?2. For Orange G contents up to 6.34 mmol dm?3, total mineralization at 100 mA cm?2 was also more easily reached in the divided cell. The mineralization current efficiency always rose at lower current density and higher dye content. The dye decayed obeying a pseudo-first-order kinetics and its apparent rate constant increased at higher current density. A similar electrolysis time was required for total decolorization and disappearance of Orange G, indicating that aromatic by-products were rapidly destroyed and did not accumulate in the medium. Final carboxylic acids like maleic, tartronic, acetic, formic, oxalic and oxamic were generated, whereas ammonium and sulfate were the main inorganic ions released during Orange G mineralization

  19. Water management in an industry

    OpenAIRE

    Stavrinou, Charalambos

    1994-01-01

    This project deals with water management in an industry. First of all the whole industry is divided into sections, in Chapter 1 and the processes executed in each section are briefly described. In Chapter 2 water service for the industry is examined. This includes water treatment and water supply for various purposes. In this Chapter the sewage system of the industry is also ex~mined, i.e. where the discharged water and effluent from the various processes is discharged and where it t...

  20. New Frontiers in the Digital Divide : Revisiting Policy for Digital Inclusion

    DEFF Research Database (Denmark)

    Jæger, Birgit

    In a new strategy for e-government, the Danish government set the goal that in 2015 all contacts between citizens and public authorities must be conducted electronically. In accordance with EU’s strategy for e-government every citizen ought to have equal access to public services, hence the question is: How to form a policy for digital inclusion where nobody is left behind? In continuation of the EU policy it seems reasonable to argue that the public authorities now has an obligation to ‘dress up’ the citizens to serve themselves through the public e-services. Hence, policies and actions for digital inclusion becomes a central theme for the implementation of the new e-government strategy. Until now it has been voluntary whether or not citizens want to use ICT and a lot of especially senior citizens have chosen not to use the technology. However, senior citizens are not the only group affected of the e-government strategy. New frontiers in the digital divide are opening and a new group of excluded become visible: the youngsters. In this way, one of the leading Danish newspapers reports that young people lines up in town halls to get help to fill out forms, which are already available on the internet. The analysis in this paper is based on a multidisciplinary theoretical approach drawing on theories of the digital divide, theories of domestication of technology, and theories about the interplay between users and technology developed in the field of STS (Science, Technology and Society). In continuation of this theoretical framework the analysis is conducted as a mixed methods research where different kinds of knowledge are included. Hence, to analyze the Danish digital divide I draw on statistics developed by Statistics Denmark – the national agency for statistic – as well as a comprehensive qualitative study of senior citizens’ usage of ICT (Jæger, 2005). For the analysis of the policy I draw on a literature study of policy papers (Jæger & Löfgren 2010) as well as six qualitative interviews with key politicians – including the Minister of Science and Technology – and key civil servant.

  1. Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2012 September - 2013 January

    Science.gov (United States)

    Warner, Brian D.

    2013-04-01

    Lightcurves for 40 asteroids were obtained at the Palmer Divide Observatory (PDO) from 2012 September to 2013 January: 495 Eulalia, 1694 Kaiser, 2001 Einstein, 3086 Kalbaugh, 3635 Kreutz, 5806 Archieroy, 6310 Jankonke, 6447 Terrycole, 6744 Komoda, 7086 Bopp, 7560 Spudis, 8325 Trigo-Rodriguez, 11149 Tateshina, 11709 Eudoxos, (13245) 1998 MM19, (13573) 1993 FZ18, 14395 Tommorgan, 15434 Mittal, (17657) 1996 VO4, (22013) 1999 XO89, (26916) 1996 RR2, 27776 Cortland, (30878) 1992 GQ, (30981) 1995 SJ4, (31831) 1999 YL, (32626) 2001 RX64, (51371) 2000 XF15, 55844 Bicak, (55854) 1996 VS1, (63440) 2001 MD30, (66832) 1999 UE45, (70927) 1999 VX210, (72675) 2001 FP54, (86388) 2000 AT60, (90988) 1997 XS13, (123937) 2001 EX16, (136017) 2002 VH74, (192683) 1999 SO27, (330825) 2008 XE3, and 2012 TC4. Based on data and analysis in 2012 for 27776 Cortland, the previously reported period from 2009 has been revised.

  2. Natural convection in a diagonally divided square cavity filled with a porous medium

    International Nuclear Information System (INIS)

    The flow and heat transfer in a diagonally divided square cavity by an inclined plate and filled with a porous medium were numerically analyzed in this paper. Vertical walls are kept at isothermal conditions, while horizontal walls are insulated. A finite difference scheme was used to solve the dimensionless governing partial differential equations along with the corresponding boundary conditions. Computations were carried out to examine the effects of Rayleigh number (100 ? Ra ? 1000), thermal conductivity ratio between plate and fluid (0.1 ? k ? 10) and the position of the partition (45 deg., Case I and 135 deg., Case II). It was found that heat transfer is attenuated when the plate is positioned at 45 deg., the heat transfer is less than when it is at 135 deg.. (authors)

  3. A divide-and-inner product parallel algorithm for polynomial evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jie; Li, Lei [Aomori Univ. (Japan); Nakamura, Tadao [Tohoku Univ., Sendai (Japan)

    1994-12-31

    In this paper, a divide-and-inner product parallel algorithm for evaluating a polynomial of degree N (N+1=KL) on a MIMD computer is presented. It needs 2K + log{sub 2}L steps to evaluate a polynomial of degree N in parallel on L+1 processors (L{<=}2K-2log{sub 2}K) which is a decrease of log{sub 2}L steps as compared with the L-order Homer`s method, and which is a decrease of (2log{sub 2}L){sup 1/2} steps as compared with the some MIMD algorithms. The new algorithm is simple in structure and easy to be realized.

  4. Second-Level Digital Divide Mapping Differences in People's Online Skills

    CERN Document Server

    Hargittai, E

    2001-01-01

    Much of the existing approach to the digital divide suffers from an important limitation. It is based on a binary classification of Internet use by only considering whether someone is or is not an Internet user. To remedy this shortcoming, this project looks at the differences in people's level of skill with respect to finding information online. Findings suggest that people search for content in a myriad of ways and there is a large variance in how long people take to find various types of information online. Data are collected to see how user demographics, users' social support networks, people's experience with the medium, and their autonomy of use influence their level of user sophistication.

  5. Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 June - September

    Science.gov (United States)

    Warner, Brian D.

    2012-01-01

    Lightcurves for 28 asteroids were obtained at the Palmer Divide Observatory (PDO) from 2011 June to September: 903 Nealley, 1103 Sequoia, 2052 Tamriko, 2083 Smither, 2150 Nyctimene, 2272 Montezuma, 2306 Bauschinger, 4125 Lew Allen, 5571 Lesliegreen, (7660) 1993 VM1, 7933 Magritte, (16256) 2000 JM2, (16959) 1998 QE17, (17822) 1998 FM135, (18890) 2000 EV26, (27568) 2000 PT6, (31898) 2000 GC1, (32953) 1996 GF19, (32928) 1995 QZ, (33356) 1999 AM3, (35055) 1984 RB, (54234) 2000 JD16, (60365) 2000 AT109, (62117) 2000 RC102, (67404) 2000 PG26, 70030 Margaretmiller, (140428) 2001 TT94, (282081) 2000 NG. Observations of 70030 Margaretmiller indicate that the asteroid is a probable binary with a secondary period being detected but no mutual events.

  6. The quantum instanton (QI) model for chemical reaction rates: The 'Simplest' QI with one dividing surface

    International Nuclear Information System (INIS)

    A new version of the quantum instanton (QI) approach to thermal rate constants of chemical reactions is presented, namely, the simplest QI (SQI) approximation with one dividing surface (DS), referred to here as SQI1. (The SQI approximation presented originally was applicable only with two DSs.) As with all versions of the QI approach, the rate is expressed wholly in terms of the (quantum) Boltzmann operator (which, for complex systems, can be evaluated by Monte Carlo path integral methods). Test calculations on some simple model problems show the SQI1 model to be slightly less accurate than the original version of the QI approach, but it is the easiest version to implement; it requires only a constrained free-energy calculation, location of the (transition-state) DS so as to maximize this free energy, and the curvature (second derivative) of the free energy at this maximum

  7. The digital divide: Trends in global mobile and broadband Internet access from 2000-2010.

    Science.gov (United States)

    Ronquillo, Charlene; Currie, Leanne

    2012-01-01

    The digital divide is described as the gap between those who do and do not have access to digital information and communications technologies (ICT). ICTs are viewed as an indicator of infrastructure and potential for development, and are a growing platform for health information and services delivery. This study compares the penetration of mobile and broadband Internet technologies by global region from 2000 to 2010. Results illustrate the rapid growth of mobile cellular telephone subscriptions in all global regions with trends suggesting a continued increase. Little to modest gains were made in fixed broadband Internet subscriptions globally. There is a growing popularity of mobile subscriptions with use of data communications, exceeding the numbers of fixed Internet subscriptions. This comparison reveals current strengths that can be built on and highlights the importance of awareness of global trends and using such knowledge to inform design and delivery of ICT-based health services. PMID:24199118

  8. Fitness for service evaluation of cracked divider plate bolt locking tabs for nuclear steam generators

    International Nuclear Information System (INIS)

    This paper is to address the structural integrity issues related to continued service without repair or replacement for cracked locking tabs on divider plates of nuclear steam generators. Significantly high residual stress introduced by cold bending of locking tabs at installation was simulated by elastic-plastic finite element method and considered in the fitness for service evaluation. Significant work hardening resulted from the accumulation of large and inhomogeneous plastic deformation introduced by the in situ bending was quantified and considered. Failure and degradation mechanisms for crack stability and propagation were identified. Linear elastic fracture mechanics (LEFM) theory with crack tip plastic zone correction was adopted to establish critical crack sizes. Life of safe operation of the cracked locking tabs from inspected crack sizes to the critical crack sizes was then evaluated. Initial crack sizes at installation were also established through a highly contrived backward fitting evaluation procedure.

  9. Design and Modeling of Symmetric Three Branch Polymer Planar Optical Power Dividers

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2013-04-01

    Full Text Available Two types of polymer-based three-branch symmetric planar optical power dividers (splitters were designed, multimode interference (MMI splitter and triangular shape-spacing splitter. By means of modeling the real structures were simulated as made of Epoxy Novolak Resin on silicon substrate, with silica buffer layer and polymethylmethacrylate as protection cover layer. The design of polymer waveguide structure was done by Beam Propagation Method. After comparing properties of both types of the splitters we have demonstrated that our new polymer based triangular shaped splitter can work simultaneously in broader spectrum, the only condition would be that the waveguides are single-mode guiding. It practically means that, what concerns communication wavelengths, it can on principle simultaneously operate at two mainly used wavelengths, 1310 and 1550 nm.

  10. Upon Further Review: VI. An Examination of Previous Lightcurve Analysis from the Palmer Divide Observatory

    Science.gov (United States)

    Warner, Brian D.

    2011-04-01

    Updated results of lightcurve analysis are given for 31 asteroids previously reported from the Palmer Divide Observatory (PDO). The original images were remeasured to obtain new data sets using the latest version of MPO Canopus photometry software, analysis tools, and revised techniques for linking observing runs that ranged from several days to several weeks. Moderately to significantly different results were found for: 301 Bavaria, 436 Patricia, 507 Laodica, 549 Jessonda, 585 Bilkis, 596 Scheila, 607 Jenny, 630 Euphemia, 875 Nymphe, 912 Maritima, 926 Imhilde, 1177 Gonnessia, 1203 Nanna, 1333 Cevenola, 1679 Nevanlinna, 1796 Riga, 2000 Herschel, 2266 Tchaikovsky, 2460 Mitlincoln, 2494 Inge, 3915 Fukushima, 3940 Larion, 4091 Lowe, 4209 Briggs, 4431 Holeungholee, 4690 Strasbourg, 5390 Huichiming, 5940 Feliksobolev, (16558) 1991 VQ2, (18108) 2000 NT5, and (45646) 2000 EE45. This is expected to be the final paper in a current series that has examined results obtained during the initial years of the asteroid lightcurve program at PDO.

  11. Analysing the thermal state of voltage transformer based on resistive voltage divider

    Science.gov (United States)

    Lebedev, V.; Zhukov, V.; Yablokov, A.

    2015-10-01

    We performed a simulation of the thermal state of a resistive voltage divider based on an equation of heat conductivity with internal sources of heat, solving this equation by using two numerical procedures. We also conducted experimental research regarding transformer thermal state on a laboratory stand. We obtained numerical results of the above heat conductivity equation, taking into account the supply of heat energy from internal sources, and compared the results of our calculations with our experimental data. Transformer thermal state simulation and numerical solution procedures enable us to formulate and resolve the problems of choosing optimal transformer design and operating modes, ensuring maximum measuring accuracy when limiting the thermal state of resistive elements.

  12. Mobile Phones Bridging the Digital Divide for Teens in the US?

    DEFF Research Database (Denmark)

    Brown, Katie; Campbell, Scott

    2011-01-01

    In 2009, just 27% of American teens with mobile phones reported using their devices to access the internet. However, teens from lower income families and minority teens were significantly more likely to use their phones to go online. Together, these surprising trends suggest a potential narrowing of the digital divide, offering internet access to those without other means of going online. This is an important move, as, in today’s society, internet access is central to active citizenship in general and teen citizenship in particular. Yet the cost of this move toward equal access is absorbed by those who can least afford it: Teenagers from low income households. Using survey and focus group data from a national study of “Teens and Mobile Phone Use” (released by Pew and the University of Michigan in 2010), this article helps identify and explain this and other emergent trends for teen use (as well as non-use) of the internet through mobile phones.

  13. Digital Divide: How Do Home Internet Access and Parental Support Affect Student Outcomes?

    Directory of Open Access Journals (Sweden)

    Jing Lei

    2012-03-01

    Full Text Available This study examined the relationship between home Internet access/parental support and student outcomes. Survey data were collected from 1,576 middle school students in China. Data were analyzed using descriptive analysis, independent-samples T-test, and regression analysis. Results indicate that students who had home Internet access reported higher scores than those without home Internet on all three dimensions: Computer and Internet self-efficacy, Attitudes towards technology and Developmental outcomes. Home Internet access and parental support were significantly positively associated with technology self-efficacy, interest in technology, perceived importance of the Internet, and perceived impact of the Internet on learning. Findings from this study have significant implications for research and practice on how to narrow down the digital divide.

  14. Design of High speed Low Power Reversible Vedic multiplier and Reversible Divider

    Directory of Open Access Journals (Sweden)

    Srikanth G Department of Electronics & Communication Engineerig, Indur Institute of Engineering & Technology, Siddipet, Medak, JNTUH University, Telangana, India.

    2014-09-01

    Full Text Available This paper bring out a 32X32 bit reversible Vedic multiplier using "Urdhva Tiryakabhayam" sutra meaning vertical and crosswise, is designed using reversible logic gates, which is the first of its kind. Also in this paper we propose a new reversible unsigned division circuit. This circuit is designed using reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register with parallel load line. The reversible vedic multiplier and reversible divider modules have been written in Verilog HDL and then synthesized and simulated using Xilinx ISE 9.2i. This reversible vedic multiplier results shows less delay and less power consumption by comparing with array multiplier.

  15. The exhibition Namibia-Germany: a shared/divided history. Resistance, violence, memory

    Directory of Open Access Journals (Sweden)

    Clara Himmelheber

    2014-10-01

    Full Text Available The year 2004 was the centenary of the outbreak of a colonial war in former German South West Africa in which thousands of Africans were killed by the colonial power. Although of crucial importance for Namibia, the war had not entered public memory in Germany. The exhibition aimed at presenting colonial history, as well as the contemporary relationships between the two countries, showing a ‘shared’ and a ‘divided’ history. The exhibition created a public debate, which certainly supported the initiative of the German Minister of Economic Co-operation and Development to deliver an apology at the commemoration in August 2004 in Namibia. The article is a post-reflection of one of the co-curators on the exhibition putting it into a larger context and reviewing it concurrently.

  16. Divide and Pacify : Strategic Social Policies and Political Protests in Postcommunist Democracies

    DEFF Research Database (Denmark)

    Vanhuysse, Pieter

    2006-01-01

    This book argues that social policies were used strategically by governments in early transitions to democracy to prevent massive strikes and social protests. Against all expectations, and despite dramatic increases in poverty, unemployment, and social inequalities, the Central and Eastern European transitions from communism to market democracy in the 1990s have been remarkably peaceful. This book proposes a new explanation for this unexpected political quiescence. It shows how reforming governments in Poland, Hungary and the Czech Republic have been able to prevent massive waves of strikes and protests by the strategic use of welfare state programs such as pensions and unemployment benefits. Divide and Pacify explains how social policies were used to prevent massive job losses with softening labor market policies, or to split up highly aggrieved groups of workers in precarious jobs by sending some of them onto unemployment benefits and many others onto early retirement and disability pensions. From a narrow economic viewpoint, these policies often appeared to be immensely costly or irresponsibly populist. Yet a more inclusive social-scientific perspective can shed new light on these seemingly irrational policies by pointing to deeper political motives and wider sociological consequences. Divide and Pacify was nominated for the American Sociological Association's Award for Distinguished Contribution to Scholarship 2006, Section on Political Sociology. Praise and reviews: "Pieter Vanhuysse…is a political scientist, an economist and a sociologist in one person. Through his original synthesis of insights from these various disciplines, he shows how an interdisciplinary perspective can help to make better sense of phenomena that appear to be puzzling, or that remain unaddressed, from the point of view of any one discipline. …Divide and Pacify…suggests that extensive social policies can be politically efficacious strategies, while never forgetting that such measures are needed to alleviate people’s suffering in the midst of traumatic social changes. …the core message of this book is important, and it has a larger relevance across many settings in which democratic governments face the task of implementing costly reforms in complex and uncertain policy environments." –János Kornai, Harvard University "Divide and Pacify contains a provocative thesis about the manner in which political strategy was used to consolidate democracy in post-communist Hungary, Poland, and the Czech Republic. Pieter Vanhuysse develops a tight argument emphasizing the strategic use of welfare and unemployment compensation policies by a government to nip potential collective action against it in the bud. By breaking up social networks that might otherwise facilitate protest, through unemployment and induced early retirement, governments were able to survive otherwise difficult economic circumstances. This novel argument linking economics, politics, sociology, and demography should stimulate wide-ranging debate about the strategic uses of social policy." - Kenneth Shepsle, Professor, Harvard University and Fellow, American Academy of Sciences "In post-communist Europe, international advice—for example from the International Monetary Fund and the World Bank—to reforming governments focused heavily on economic policy. The political imperative, in contrast, was a set of policies generous enough to maintain continuing support for the overall reforms. The great value of this book is that it addresses both strategic policy directions simultaneously. Specifically, it analyzes how policies that are sub-optimal in economic terms (work in the grey economy, easy access to unemployment benefits, fiscally expensive early retirement) can be argued to be optimal (or at least roughly so) when considering economics and politics together. As such, the book offers a rich political economy perspective on post-communist reforms." – Nicholas Barr, Professor of Public Economics, London School of Economics and Political Science" In the countries of Central Euro

  17. Toward a High Performance Tile Divide and Conquer Algorithm for the Dense Symmetric Eigenvalue Problem

    KAUST Repository

    Haidar, Azzam

    2012-01-01

    Classical solvers for the dense symmetric eigenvalue problem suffer from the first step, which involves a reduction to tridiagonal form that is dominated by the cost of accessing memory during the panel factorization. The solution is to reduce the matrix to a banded form, which then requires the eigenvalues of the banded matrix to be computed. The standard divide and conquer algorithm can be modified for this purpose. The paper combines this insight with tile algorithms that can be scheduled via a dynamic runtime system to multicore architectures. A detailed analysis of performance and accuracy is included. Performance improvements of 14-fold and 4-fold speedups are reported relative to LAPACK and Intel\\'s Math Kernel Library.

  18. The skill-divide in job quality: a cross-national analysis of 28 countries.

    Science.gov (United States)

    Stier, Haya

    2015-01-01

    This study focuses on the skill divide in job quality and the role of social institutions in structuring the relation of workers' qualifications to the attributes of their jobs. Four measures of job quality are examined: job security, job achievement, job content and work schedule flexibility. The study is based on the 2005 ISSP module on work orientations and encompasses 28 countries. Obtained through multilevel modeling, the findings show that low-skilled workers are disadvantaged in all aspects of job quality. However, skill inequality in the quality of employment depends on countries' characteristics, with declining inequality in countries at higher levels of technological development and to some extent also in times of technological growth. At times of high unemployment, skill disparities in job security widen while on other measures of job quality they decline. Under high market regulation, the low skilled enjoy better job security but on other measures, skill inequalities increase. PMID:25432604

  19. Evaluating the Spectrum of Unlocked Injection Frequency Dividers in Pulling Mode

    Directory of Open Access Journals (Sweden)

    Alessandro Lo Schiavo

    2013-09-01

    Full Text Available We study the phenomenon of periodic pulling which occurs in certain integrated microcircuits of relevant interest in applications, namely the injection-locked frequency dividers (ILFDs. They are modelled as second-order driven oscillators working in the subharmonic (secondary resonance regime, i.e., when the self-oscillating frequency is close (resonant to an integer submultiple n of the driving frequency. Under the assumption of weak injection, we find the spectrum of the system’s oscillatory response in the unlocked mode through closed-form expressions, showing that such spectrum is double-sided and asymmetric, unlike the single-sided spectrum of systems with primary resonance (n=1. An analytical expression for the amplitude modulation of the oscillatory response is also presented. Numerical results are presented to support theoretical relations derived.

  20. Inequalities and the digital divide in children and young people's internet use: findings from the UK Children Go Online project

    OpenAIRE

    Livingstone, Sonia; Bober, Magdalena; Helsper, Ellen

    2005-01-01

    Executive summary. Considerable academic and policy attention has recently addressed the so-called ‘digital divide’ in the UK and elsewhere. Yet very little research has addressed children and young people in relation to the digital divide. This report examines the extent and source of any inequalities in internet access and use among 9-19 year olds in the UK. Drawing on data from the ‘UK Children Go Online’ project, we ask: • Is there is digital divide among children and young people? If so,...

  1. Social suffering and the culture of compassion in a morally divided China.

    Science.gov (United States)

    Kuah-Pearce, Khun Eng; Kleinman, Arthur; Harrison, Emily

    2014-01-01

    This collection of essays opens a critical examination of compassionate acts responding to social suffering in the intensely complex moral context of a rapidly changing and globalizing China. Jeanne Shea describes self-compassion among older women in China as a post-revolutionary response to changing opportunities and resistance to consumerism. Khun Eng Kuah-Pearce's essay frames the Buddhist organizations as NGOs and shows compassion being mobilized and its acts being spiritual-philanthropic, not political. The next three papers illuminate the complexity of mobility in a moral sea of changing values. Even as modernity facilitates movement of people away from suffering, the grinding of entangled moral experiences within the mobile group can be the cause of suffering. Shu-Min Huang critiques 'cultural petrification' as the diasporic Yunnan Chinese community in Thailand attempt to preserve the cultural forms and procedures of the world they left behind. Likewise, Richard Madsen shows that the idea of a universalized cultural heritage fails in the face of the 'micro-ecologies'. And yet the modern impulse to universalize beyond China has important implications for transnational compassion and cooperation. The work of the humanitarian organization Médecins Sans Frontières in China, discussed by Kuah-Pearce and Guiheux, challenges the universality of global humanitarian actions. Following the series of essays threaded across intersections of compassion, suffering, and a morally-divided China, the collection closes by looking at the West. Iain Wilkinson discusses the origins of social suffering as a focus of the social sciences, as well as the difficulties of making engaged compassion its task in a morally-divided world. PMID:24524752

  2. Development and Field Evaluation of a Rotary Hydraulic Divider for Canola Harvesting

    Directory of Open Access Journals (Sweden)

    Kamgar

    2009-04-01

    Full Text Available Oil seed rape is an important non-cereal crop used mainly for edible oil production. Canola pods are fragile and its branches are twisted together at harvesting time. Harvesting with a conventional combine can pull off twisted branches and cause appreciable losses in the vicinity of divider at combine header. In this study, a hydraulic rotary divider was designed and developed to separate twisted pods and reduce the grain loss. The device is made up of two cylinders and a number of fingers, the cylinders rotate in opposite direction and fingers move in and out through holes on cylinder walls. The assembly was expected to separate the twisted pods and reduce grain loss. A hydraulic motor driven by combine hydraulic system was used to rotate the separating cylinders. The separating assembly was installed on righthand side of the combine harvester header. A split-plot experiment was used to evaluate the performance of the unit. Field tests were carried out at combine forward speed of 1.5 kmh-1. Variables were: cylinders rotary speed in three levels (50, 75 and 100 rpm, the number of fingers in three levels (16, 12 and 8, and the tests were conducted with and without combine reel. Two different positions of finger protrusion were also considered in field tests. The results were compared with those of a conventional combine header. The results show that the medium rotational speed (75 rpm exhibited lowest seed loss. Furthermore, as the number of fingers increased, the seed loss tended to decrease. The seed loss also decreased in the presence of combine reel. Also, findings showed there is no significant difference between the two protrusions trajectories of fingers. A twenty percent decrease in seed loss was observed at rotary speed of 75 rpm and number of fingers of 16 in the presence of combine reel.

  3. A High Resolution Carbon Dioxide Record for the Last Deglaciation from the WAIS Divide Ice Core

    Science.gov (United States)

    Marcott, S. A.; Bauska, T. K.; Edwards, J. S.; Kalk, M. L.; Lee, J. E.; Rosen, J. L.; Sowers, T. A.; Brook, E.

    2012-12-01

    Establishing the role of carbon dioxide, both as a feedback and forcing, during the most recent deglaciation provides the best opportunity to understand the relationship between the carbon cycle, ice sheets, and global temperatures. This requires a precise, high-resolution, well dated record of atmospheric CO2. Existing Antarctic ice core records have provided insight into both the timing of CO2 changes and likely sources, but lack the temporal resolution to address some important problems. CO2 data from the WAIS Divide ice core will yield the highest resolution and best dated CO2 record covering the last ~60 ka, due to the high accumulation rate at the site (presently 20 cm/yr) and excellent chronological control from layer counting and high resolution correlations to well dated ice core and other climate records. Here we present a CO2 record from the WAIS Divide Ice Core (WDC) in Antarctica for the period 25,000 - 8,000 years BP. Our record is in excellent agreement with previous reconstructions of CO2 during the last 20,000 years after accounting for temporal smoothing of those other records due to diffusion in the firn. However, several abrupt changes in CO2 occur in the WDC record that have not been fully documented elsewhere. Several of these abrupt CO2 changes occur synchronously with changes in CH4 at key climate transitions, including an abrupt CO2 increases during Heinrich stadial 1, the onset of the Bølling-Allerød, and end of the Younger Dryas. Deglacial CO2 rise in the WDC occurs at ~18 ka on our newest chronology. Owing to the small delta-age and excellent chronologic constraints for the WDC, CO2 variability can now be documented at the centennial or shorter time scale. Thus, the timing and amplitude of abrupt changes in CO2 is very precisely resolved, which has allowed for the most well constrained greenhouse gas record to date.

  4. Subglacial lake matters: piracy on a divide between thawed and frozen bed

    Science.gov (United States)

    Carter, S. P.; Bougamont, M. H.; Christoffersen, P.; Fricker, H. A.; Lipscomb, W. H.; Price, S. F.

    2011-12-01

    The two most populated active subglacial lake districts in Antarctica, upper Kamb Ice Stream and lower Whillans Ice Stream, occur along boundaries between where temperature models predict net basal freezing and net basal accretion. This occurs in part due to a basal traction contrast, which creates a ridge in the ice surface and creates a pressure seal; this impedes the downstream movement of water until a subglacial lake flood occurs. Here we use a model for basal water routing, which incorporates subglacial floods and a realistic term for effective pressure, to explore the ability of these floods to provide water to areas of net basal accretion and thus maintain basal lubrication. We hypothesize that these floods can distribute sufficient water to most of the regions experiencing net basal freezing; the exception being those nearest to the lakes themselves, Discharge in these regions likely occurs via narrow subglacial conduits. Over time this will cause ice downstream of the dam to thicken and pre-flood lake levels to increase until water ultimately exits the lake via an alternate route i.e. water piracy. Once piracy occurs, water is no longer supplied along the former flowpath and ice stream shutdown accelerates. We conclude that the formation and quasi-periodic flooding of lakes at the basal melt/ basal freezing boundary is a critical process in accelerating ice stream shutdown.

  5. Electron cryotomography of ESCRT assemblies and dividing Sulfolobus cells suggests that spiraling filaments are involved in membrane scission

    OpenAIRE

    Dobro, Megan J; Samson, Rachel Y.; Yu, Zhiheng; McCullough, John; Ding, H Jane; Chong, Parkson Lee-Gau; Bell, Stephen D; Jensen, Grant J

    2013-01-01

    ESCRT filaments wrap helically around liposomes and assemble into various helical structures in vitro. Dividing Sulfolobus cells further exhibit a thin, dynamic belt coating division furrows. Together these data suggest that spiraling filaments are involved in membrane scission.

  6. Information and Communication Technologies and the Digital Divide in Africa: A Review of the Periodical Literature, 2000-2012

    OpenAIRE

    Susan E. Russell; Tom Steele

    2013-01-01

    The digital revolution has transformed much of the global economy. Information and communication technologies (ICTs) play a key role in this revolution. However, not everyone has equal access to these technologies. This gap exists on multiple levels, whether between individuals, small segments within a population, countries, or global regions. The term used to refer to this inequality is the digital divide. This bibliography focuses on recent literature written to describe the digital divide ...

  7. Information and Communication Technologies and the Digital Divide in Africa: A Review of the Periodical Literature, 2000-2012

    Directory of Open Access Journals (Sweden)

    Susan E. Russell

    2013-04-01

    Full Text Available The digital revolution has transformed much of the global economy. Information and communication technologies (ICTs play a key role in this revolution. However, not everyone has equal access to these technologies. This gap exists on multiple levels, whether between individuals, small segments within a population, countries, or global regions. The term used to refer to this inequality is the digital divide. This bibliography focuses on recent literature written to describe the digital divide on the African continent.

  8. Water, Water Everywhere

    Science.gov (United States)

    Keeler, Rusty

    2009-01-01

    Everybody knows that children love water and how great water play is for children. The author discusses ways to add water to one's playscape that fully comply with health and safety regulations and are still fun for children. He stresses the importance of creating water play that provides children with the opportunity to interact with water.

  9. Sizing up to Divide: Mitotic Cell-Size Control in Fission Yeast.

    Science.gov (United States)

    Wood, Elizabeth; Nurse, Paul

    2015-11-13

    Schizosaccharomyces pombe is a good model to study cell-size control. These cells integrate size information into cell cycle controls at both the G1/S and G2/M transitions, although the primary control operates at the entry into mitosis. At G2/M there is both a size threshold, demonstrated by the fact that cells divide when they reach 14 ?m in length, and also correction around this threshold, evident from the narrow distribution of sizes within a population. This latter property is referred to as size homeostasis. It has been argued that a population of cells accumulating mass in a linear fashion will have size homeostasis in the absence of size control, if cycle time is controlled by a fixed timer. Because fission yeast cells do not grow in a simple linear fashion, they require a size-sensing mechanism. However, current models do not fully describe all aspects of this control, especially the coordination of cell size with ploidy. PMID:26566110

  10. Cocaine choice procedures in animals, humans, and treatment-seekers: Can we bridge the divide?

    Science.gov (United States)

    Moeller, Scott J; Stoops, William W

    2015-11-01

    Individuals with cocaine use disorder chronically self-administer cocaine to the detriment of other rewarding activities, a phenomenon best modeled in laboratory drug-choice procedures. These procedures can evaluate the reinforcing effects of drugs versus comparably valuable alternatives under multiple behavioral arrangements and schedules of reinforcement. However, assessing drug-choice in treatment-seeking or abstaining humans poses unique challenges: for ethical reasons, these populations typically cannot receive active drugs during research studies. Researchers have thus needed to rely on alternative approaches that approximate drug-choice behavior or assess more general forms of decision-making, but whether these alternatives have relevance to real-world drug-taking that can inform clinical trials is not well-understood. In this mini-review, we (A) summarize several important modulatory variables that influence cocaine choice in nonhuman animals and non-treatment seeking humans; (B) discuss some of the ethical considerations that could arise if treatment-seekers are enrolled in drug-choice studies; (C) consider the efficacy of alternative procedures, including non-drug-related decision-making and 'simulated' drug-choice (a choice is made, but no drug is administered) to approximate drug choice; and (D) suggest opportunities for new translational work to bridge the current divide between preclinical and clinical research. PMID:26432174

  11. Evaluation of copper for divider subassembly in MCO Mark IA and Mark IV scrap fuel baskets

    International Nuclear Information System (INIS)

    The K Basin Spent Nuclear Fuel (SNF) Project Multi-Canister Overpack (MCO) subprojection eludes the design and fabrication of a canister that will be used to confine, contain, and maintain fuel in a critically safe array to enable its removal from the K Basins, vacuum drying, transport, staging, hot conditioning, and interim storage (Goldinann 1997). Each MCO consists of a shell, shield plug, fuel baskets (Mark IA or Mark IV), and other incidental equipment. The Mark IA intact and scrap fuel baskets are a safety class item for criticality control and components necessary for criticality control will be constructed from 304L stainless steel. It is proposed that a copper divider subassembly be used in both Mark IA and Mark IV scrap baskets to increase the safety basis margin during cold vacuum drying. The use of copper would increase the heat conducted away from hot areas in the baskets out to the wall of the MCO by both radiative and conductive heat transfer means. Thus copper subassembly will likely be a safety significant component of the scrap fuel baskets. This report examines the structural, cost and corrosion consequences associated with using a copper subassembly in the stainless steel MCO scrap fuel baskets

  12. Dividing the Force Concept Inventory into two equivalent half-length tests

    Science.gov (United States)

    Han, Jing; Bao, Lei; Chen, Li; Cai, Tianfang; Pi, Yuan; Zhou, Shaona; Tu, Yan; Koenig, Kathleen

    2015-06-01

    The Force Concept Inventory (FCI) is a 30-question multiple-choice assessment that has been a building block for much of the physics education research done today. In practice, there are often concerns regarding the length of the test and possible test-retest effects. Since many studies in the literature use the mean score of the FCI as the primary variable, it would be useful then to have different shorter tests that can produce FCI-equivalent scores while providing the benefits of being quicker to administer and overcoming the test-retest effects. In this study, we divide the 1995 version of the FCI into two half-length tests; each contains a different subset of the original FCI questions. The two new tests are shorter, still cover the same set of concepts, and produce mean scores equivalent to those of the FCI. Using a large quantitative data set collected at a large midwestern university, we statistically compare the assessment features of the two half-length tests and the full-length FCI. The results show that the mean error of equivalent scores between any two of the three tests is within 3%. Scores from all tests are well correlated. Based on the analysis, it appears that the two half-length tests can be a viable option for score based assessment that need to administer tests quickly or need to measure short-term gains where using identical pre- and post-test questions is a concern.

  13. Tackling the urban health divide though enabling intersectoral action on malnutrition in Chile and Kenya.

    Science.gov (United States)

    Pridmore, Pat; Carr-Hill, Roy; Amuyunzu-Nyamongo, Mary; Lang'o, Daniel; McCowan, Tristan; Charnes, Gabriela

    2015-04-01

    As momentum grows for a sustainable urbanisation goal in the post-2015 development agenda, this paper reports on an action research study that sought to tackle the urban health divide by enabling intersectoral action on social determinants at the local level. The study was located in the cities of Mombasa in Kenya and Valparaíso in Chile, and the impact of the intervention on child nutrition was evaluated using a controlled design. The findings showed that an action research process using the social educational process known as PLA could effectively build the capacity of multisectoral teams to take coordinated action which in turn built the capacity of communities to sustain them. The impact on child nutrition was inconclusive and needed to be interpreted within the context of economic collapse in the intervention area. Four factors were found to have been crucial for creating the enabling environment for effective intersectoral action (i) supportive government policy (ii) broad participation and capacity building (iii) involving policy makers as advisors and establishing the credibility of the research and (iii) strengthening community action. If lessons learned from this study can be adapted and applied in other contexts then they could have a significant economic and societal impact on health and nutrition equity in informal urban settlements. PMID:25758598

  14. A Sub-band Divided Ray Tracing Algorithm Using the DPS Subspace in UWB Indoor Scenarios

    DEFF Research Database (Denmark)

    Gan, Mingming; Xu, Zhinan

    2015-01-01

    Sub-band divided ray tracing (SDRT) is one technique that has been extensively used to obtain the channel characteristics for ultra-wideband (UWB) radio wave propagation in realistic indoor environments. However, the computational complexity of SDRT scales directly with the number of sub-bands. Although we have proposed a low-complexity SDRT algorithm for one terminal position [1], the computational complexity i s still extremely high when involving multiple mobile terminal positions. Moreover, some indoor positioning techniques require for high positioning accuracy data from measurements/simulations with a very fine spatial resolution. To cope with this, we propose an algorithm to reduce the computational complexity of SDRT for multiple mobile terminal positions. The algorithm uses a projection of all propagation paths on a subspace spanned by two-dimensional discrete prolate spheroidal (DPS) sequences at each sub-band. It is important to note that, since the geometrical information of the propagation paths is the same in all sub-bands, the subspace dimension and basis coefficients in frequency dimension do not need to be recalculated at different sub-bands. We justify the simplifications of the proposed method by numerical simulations. Furthermore, we evaluate the effect of antenna characteristics on the proposed algorithm. Our proposed algorithm reduces the computational complexity by more than one order of magnitude for indoor scenarios.

  15. Critical transition between cohesive and population-dividing responses to change.

    Science.gov (United States)

    Muneepeerakul, Rachata; Qubbaj, Murad R; Aggarwal, Rimjhim M; Anderies, John M; Janssen, Marco A

    2012-12-01

    Globalization and global climate change will probably be accompanied by rapid social and biophysical changes that may be caused by external forcing or internal nonlinear dynamics. These changes often subject residing populations (human or otherwise) to harsh environments and force them to respond. Research efforts have mostly focused on the underlying mechanisms that drive these changes and the characteristics of new equilibria towards which populations would adapt. However, the transient dynamics of how populations respond under these new regimes is equally, if not more, important, and systematic analysis of such dynamics has received less attention. Here, we investigate this problem under the framework of replicator dynamics with fixed reward kernels. We show that at least two types of population responses are possible--cohesive and population-dividing transitions--and demonstrate that the critical transition between the two, as well as other important properties, can be expressed in simple relationships between the shape of reward structure, shift magnitude and initial strategy diversity. Importantly, these relationships are derived from a simple, yet powerful and versatile, method. As many important phenomena, from political polarization to the evolution of distinct ecological traits, may be cast in terms of division of populations, we expect our findings and method to be useful and applicable for understanding population responses to change in a wide range of contexts. PMID:22809848

  16. The private-public literacy divide amid educational reform in Qatar: What does PISA tell us?

    Science.gov (United States)

    Cheema, Jehanzeb R.

    2015-04-01

    The education system in Qatar comprises of both private schools, which receive money through student fees, and public schools, which are fully government-funded. In the mid-2000s, Qatar started its transition towards an independent school model with the aim of eventually converting all public schools into government-supported independent schools. The idea was to give public schools more autonomy in terms of hiring decisions, adoption of curriculum and textbooks, and budget spending, enabling them to emulate some of the private schools' strategies for turning out successful students. This study examines evidence from the 2006-2012 administrations of the Program for International Student Assessment (PISA) in Qatar in order to evaluate whether or not recent educational reform efforts in this country have succeeded in bridging the literacy divide between private and public schools. The results, presented in a number of detailed tables and discussed in the last part of the article, indicate that there is a significant difference in key literacy skills between the two types of schools. Private schools were found to outperform their public counterparts in areas such as mathematics, reading and science, both before and after controlling for important student-level differences, and this gap has evidently persisted from 2006 to 2012.

  17. Biosynthesis of copper nanoparticles and its effect on actively dividing cells of mitosis in Allium cepa.

    Science.gov (United States)

    Nagaonkar, Dipali; Shende, Sudhir; Rai, Mahendra

    2015-01-01

    Nanobiotechnological application of copper nanoparticles has paved the way for advancement in agriculture owing to its bactericidal and fungicidal activities. Recently, researchers have focussed on bioinspired synthesis of copper nanoparticles as a viable alternative to existing physicochemical techniques. For the commercialization of nanocopper, the toxicity evaluation is a major issue. In this context, Citrus medica (L.) fruit extract-mediated copper nanoparticles were synthesized and its different concentrations (10, 20, 40, 60, 80, and 100 µg mL(-1) ) were evaluated for its effect on actively dividing cells of Allium cepa. The study clearly revealed that copper nanoparticles increased mitotic index up to the concentration of 20 µg mL(-1) . In addition, a gradual decline in mitotic index and increase in abnormality index was observed as the concentration of copper nanoparticles and treatment duration were increased. Aberrations in chromosomal behavior such as sticky and disturbed chromosomes in metaphase and anaphase, c-metaphase, bridges, laggard, disturbed telophase, and vacuolated nucleus were also observed. PMID:25607830

  18. Mutations in KATNB1 cause complex cerebral malformations by disrupting asymmetrically dividing neural progenitors.

    Science.gov (United States)

    Mishra-Gorur, Ketu; Ça?layan, Ahmet Okay; Schaffer, Ashleigh E; Chabu, Chiswili; Henegariu, Octavian; Vonhoff, Fernando; Akgümü?, Gözde Tu?ce; Nishimura, Sayoko; Han, Wenqi; Tu, Shu; Baran, Burçin; Gümü?, Hakan; Dilber, Cengiz; Zaki, Maha S; Hossni, Heba A A; Rivière, Jean-Baptiste; Kayserili, Hülya; Spencer, Emily G; Rosti, Rasim Ö; Schroth, Jana; Per, Hüseyin; Ça?lar, Caner; Ça?lar, Ça?ri; Dölen, Duygu; Baranoski, Jacob F; Kumanda?, Sefer; Minja, Frank J; Erson-Omay, E Zeynep; Mane, Shrikant M; Lifton, Richard P; Xu, Tian; Keshishian, Haig; Dobyns, William B; Chi, Neil C; Šestan, Nenad; Louvi, Angeliki; Bilgüvar, Kaya; Yasuno, Katsuhito; Gleeson, Joseph G; Günel, Murat

    2014-12-17

    Exome sequencing analysis of over 2,000 children with complex malformations of cortical development identified five independent (four homozygous and one compound heterozygous) deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule-severing enzyme Katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of Katanin, and other microtubule-associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype. In the developing Drosophila optic lobe, kat80 loss specifically affects the asymmetrically dividing neuroblasts, which display supernumerary centrosomes and spindle abnormalities during mitosis, leading to cell cycle progression delays and reduced cell numbers. Furthermore, kat80 depletion results in dendritic arborization defects in sensory and motor neurons, affecting neural architecture. Taken together, we provide insight into the mechanisms by which KATNB1 mutations cause human cerebral cortical malformations, demonstrating its fundamental role during brain development. PMID:25521378

  19. An Efficient Similarity Digests Database Lookup - A Logarithmic Divide & Conquer Approach

    Directory of Open Access Journals (Sweden)

    Frank Breitinger

    2014-09-01

    Full Text Available Investigating seized devices within digital forensics represents a challenging task due to the increasing amount of data. Common procedures utilize automated file identification, which reduces the amount of data an investigator has to examine manually. In the past years the research field of approximate matching arises to detect similar data. However, if n denotes the number of similarity digests in a database, then the lookup for a single similarity digest is of complexity of O(n. This paper presents a concept to extend existing approximate matching algorithms, which reduces the lookup complexity from O(n to O(log(n. Our proposed approach is based on the well-known divide and conquer paradigm and builds a Bloom filter-based tree data structure in order to enable an efficient lookup of similarity digests. Further, it is demonstrated that the presented technique is highly scalable operating a trade-off between storage requirements and computational efficiency. We perform a theoretical assessment based on recently published results and reasonable magnitudes of input data, and show that the complexity reduction achieved by the proposed technique yields a 220-fold acceleration of look-up costs.

  20. A CRITICAL EVALUATION OF INDIAN GOVERNMENT’S STRATEGIES TO BRIDGE DIGITAL DIVIDE

    Directory of Open Access Journals (Sweden)

    Nityesh BHATT

    2006-01-01

    Full Text Available Emergence of Information and Communication Technology (ICT has been a landmark for India. In one way, this sunshine sector has been instrumental in the economic growth of country and has glorified its image in the whole world but on the other end, it has also created a digital divide in our society. BBC's Jill McGivering reports that the IT revolution is only changing some lives in the world's largest democracy. (Bagla,2005 A small section of society is harnessing it fully for their advantage while the masses are even not aware of it. UNESCO report 1998 also stated that for the majority of the world’s population, telephones are a technology beyond reach; food, sanitation and literacy are more urgent needs. How can we reconcile major commitments of energy and funds to ICTs when more basic human needs remain unfulfilled? The conventional, even formulaic, answer to the alleged conflict between investment in ICTs and investment in meeting basic human needs is, "We need to do both.There is no contradiction between ICTs and other critical human and social goals." (Keniston, 2002 ICT sector has potential of reviving the hopes and fortunes of these deprived and hatred section of society. Application of ICT in the form of E-Governance possess the potential to bridge the gulf between the urban 'technology haves' and rural ‘have nots', within and among the countries. (Annan, 2002

  1. Atoms can be divided into three categories: polar, non-polar and hydrogen atom

    CERN Document Server

    You, Pei-Lin

    2010-01-01

    Since the time of Rutherford 1911) physicists and chemists commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, atoms do not have permanent electric dipole moment (EDM), so that there is no polar atom in nature. In the fact, the idea is untested hypothesis. After ten years of intense research, our experiments showed that atoms can be divided into three categories: polar, non-polar and hydrogen atom. Alkali atoms are all polar atoms. The EDM of a Sodium, Potassium, Rubidium and Cesium atom in the ground state have been obtained as follows: d(Na)=1.28*10 to-8 power e.cm; d(K)=1.58*10 to-8 power e.cm; d(Rb)=1.70 *10 to-8 power e.cm; d(Cs)=1.86*10 to-8 power e.cm. All kind of atoms are non-polar atoms except for alkali and hydrogen atoms. Hydrogen atom is quite distinct from the others. The ground state in hydrogen is non-polar atom(d=0) but the excited state is polar atom, for example, the first excited state has a large EDM: d(H)=3ea=1.59*10 to-8 power e....

  2. Evaluation of copper for divider subassembly in MCO Mark IA and Mark IV scrap fuel baskets

    Energy Technology Data Exchange (ETDEWEB)

    Graves, C.E.

    1997-09-29

    The K Basin Spent Nuclear Fuel (SNF) Project Multi-Canister Overpack (MCO) subprojection eludes the design and fabrication of a canister that will be used to confine, contain, and maintain fuel in a critically safe array to enable its removal from the K Basins, vacuum drying, transport, staging, hot conditioning, and interim storage (Goldinann 1997). Each MCO consists of a shell, shield plug, fuel baskets (Mark IA or Mark IV), and other incidental equipment. The Mark IA intact and scrap fuel baskets are a safety class item for criticality control and components necessary for criticality control will be constructed from 304L stainless steel. It is proposed that a copper divider subassembly be used in both Mark IA and Mark IV scrap baskets to increase the safety basis margin during cold vacuum drying. The use of copper would increase the heat conducted away from hot areas in the baskets out to the wall of the MCO by both radiative and conductive heat transfer means. Thus copper subassembly will likely be a safety significant component of the scrap fuel baskets. This report examines the structural, cost and corrosion consequences associated with using a copper subassembly in the stainless steel MCO scrap fuel baskets.

  3. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    Energy Technology Data Exchange (ETDEWEB)

    Afanasiev, Pavel, E-mail: pavel.afanasiev@ircelyon.univ-lyon1.fr

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoS{sub x} (x?4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoS{sub x} under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS{sub 2} materials with very high pore volume and specific surface area, up to 0.45 cm{sup 3}/g and 190 m{sup 2}/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoS{sub x} particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS{sub 2} with very high porosity and surface area.

  4. The potential, limitations, and challenges of divide and conquer quantum electronic structure calculations on energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jon R.; Magyar, Rudolph J.

    2012-02-01

    High explosives are an important class of energetic materials used in many weapons applications. Even with modern computers, the simulation of the dynamic chemical reactions and energy release is exceedingly challenging. While the scale of the detonation process may be macroscopic, the dynamic bond breaking responsible for the explosive release of energy is fundamentally quantum mechanical. Thus, any method that does not adequately describe bonding is destined to lack predictive capability on some level. Performing quantum mechanics calculations on systems with more than dozens of atoms is a gargantuan task, and severe approximation schemes must be employed in practical calculations. We have developed and tested a divide and conquer (DnC) scheme to obtain total energies, forces, and harmonic frequencies within semi-empirical quantum mechanics. The method is intended as an approximate but faster solution to the full problem and is possible due to the sparsity of the density matrix in many applications. The resulting total energy calculation scales linearly as the number of subsystems, and the method provides a path-forward to quantum mechanical simulations of millions of atoms.

  5. [Excision: the new prohibition that divides the society. Press review: Senegal].

    Science.gov (United States)

    1999-12-01

    Approximately 700,000 women in Senegal have suffered female genital mutilation (FGM). Now, following a vote upon legislation banning FGM, public opinion in the country over the practice is more divided than ever. The practitioners of FGM are not taking the law seriously, while politicians hesitate to openly condemn the practice, which still occurs widely in rural zones. Most of the 140 parliamentarians do not believe that laws alone can successfully end FGM in Senegal. Some deputies and feminists believe that several years of sensitization on the issue will be needed to effectively reduce the frequency with which FGM is practiced. Only optimists believe FGM will disappear on its own. The debate threatens to resurface in some areas during the year 2000 presidential election. One deputy from the governing party, originally from southern Senegal, states that he dares not tell his constituency that the president himself created the anti-FGM legislation, especially when locally elected leaders finance villages¿ FGM-related celebrations. According to a scholar of the Koran, FGM is an Islamic practice, but it is not taught in the Koran. FGM is therefore a cultural practice borne from individual choice. In Kolda, 650 km south of Dakar, the practitioners of such mutilation argue that they would rather be imprisoned than abandon the practice they consider to be an immutable component of their cultural history. PMID:12296198

  6. Identification of an antigen localized to an apparent septum within dividing chlamydiae.

    Science.gov (United States)

    Brown, W J; Rockey, D D

    2000-02-01

    The process of chlamydial cell division has not been thoroughly investigated. The lack of detectable peptidoglycan and the absence of an FtsZ homolog within chlamydiae suggest an unusual mechanism for the division process. Our laboratory has identified an antigen (SEP antigen) localized to a ring-like structure at the apparent septum within dividing chlamydial reticulate bodies (RB). Antisera directed against SEP show similar patterns of antigen distribution in Chlamydia trachomatis and Chlamydia psittaci RB. In contrast to localization in RB, SEP in elementary bodies appears diffuse and irregular, suggesting that the distribution of the antigen is developmental-stage specific. Treatment of chlamydiae with inhibitors of peptidoglycan synthesis or culture of chlamydiae in medium lacking tryptophan leads to the formation of nondividing, aberrant RB. Staining of aberrant RB with anti-SEP reveals a marked redistribution of the antigen. Within C. trachomatis-infected cells, ampicillin treatment leads to high levels of SEP accumulation at the periphery of aberrant RB, while in C. psittaci, treatment causes SEP to localize to distinct punctate sites within the bacteria. Aberrancy produced via tryptophan depletion results in a different pattern of SEP distribution. In either case, the reversal of aberrant formation results in the production of normal RB and a redistribution of SEP to the apparent plane of bacterial division. Collectively these studies identify a unique chlamydial-genus-common and developmental-stage-specific antigen that may be associated with RB division. PMID:10639437

  7. Divided attention improves delayed, but not immediate retrieval of a consolidated memory.

    Science.gov (United States)

    Kessler, Yoav; Vandermorris, Susan; Gopie, Nigel; Daros, Alexander; Winocur, Gordon; Moscovitch, Morris

    2014-01-01

    A well-documented dissociation between memory encoding and retrieval concerns the role of attention in the two processes. The typical finding is that divided attention (DA) during encoding impairs future memory, but retrieval is relatively robust to attentional manipulations. However, memory research in the past 20 years had demonstrated that retrieval is a memory-changing process, in which the strength and availability of information are modified by various characteristics of the retrieval process. Based on this logic, several studies examined the effects of DA during retrieval (Test 1) on a future memory test (Test 2). These studies yielded inconsistent results. The present study examined the role of memory consolidation in accounting for the after-effect of DA during retrieval. Initial learning required a classification of visual stimuli, and hence involved incidental learning. Test 1 was administered 24 hours after initial learning, and therefore required retrieval of consolidated information. Test 2 was administered either immediately following Test 1 or after a 24-hour delay. Our results show that the effect of DA on Test 2 depended on this delay. DA during Test 1 did not affect performance on Test 2 when it was administered immediately, but improved performance when Test 2 was given 24-hours later. The results are consistent with other findings showing long-term benefits of retrieval difficulty. Implications for theories of reconsolidation in human episodic memory are discussed. PMID:24608365

  8. Interfering with remembering and knowing: effects of divided attention at retrieval.

    Science.gov (United States)

    Skinner, Erin I; Fernandes, Myra A

    2008-02-01

    A Remember-Know paradigm was used to examine the cognitive resource requirements of recollection and familiarity memory processes at retrieval. Younger and older adults studied a list of words, and in a later auditory recognition test indicated whether each word was Remembered, Known, or New. Retrieval was performed under full or divided attention (DA) conditions, with either a digit task to numbers, or an animacy task to words, presented visually. Younger and older adults showed an increase in false Remember responses during both DA conditions, indicating a general effect of attention on illusory recollection. Both age groups also showed decreased accuracy in Know responses, but only during the word-based DA condition, indicating a material-specific effect on familiarity. Aging was associated with decreased accuracy in Remember, but not Know, responses, and with increased latency in distracting task responses under DA conditions. Results suggest that avoiding false recollective responses during retrieval requires attentional resources, whereas accurate familiarity responses require the reactivation of content-specific representations. PMID:17599796

  9. The divide within: Older active ICT users position themselves against different 'Others'.

    Science.gov (United States)

    Kania-Lundholm, Magdalena; Torres, Sandra

    2015-12-01

    Although research into older people's internet usage patterns is rapidly growing, their understandings of digital technologies, particularly in relation to how these are informed by their understandings of aging and old age, remain unexplored. This is the case because research on older active ICT users tends to regard old age as an empirically interesting part of the life-course as opposed to a theoretically profuse source of information about why and how older people engage with digital technologies. This article explores - through focus group interviews with 30 older adults (aged 66-89) - the ways in which the social position of old age is used by older active ICT users in order to make sense of how and why they engage with these technologies. In this article, positioning theory is used to shed light on how the older people interviewed positioned themselves as 'active older users' in the interviews. The analysis brings to the fore the divide that older people themselves create as they discursively position themselves against different types of ICT users and non-users (young and old) when describing how and why they engage with digital technologies. PMID:26568212

  10. The private-public law divide : Does this legal design create an abyss to children's welfare?

    DEFF Research Database (Denmark)

    Svendsen, Idamarie Leth; Kronborg, Annette

    2013-01-01

    In a Scandinavian perspective, the family and the individual have changed places during the 20th Century. Today, the law takes its starting point in the individual - not in the family. A consequence of this development is that it is no longer legally possible to relate the good family to a particular societal institution. Marriage as an institution has been individualized and the goodness of the family has to relate to the well-being of the individuals instead. This article shows that within this historical development the private-public law divide has not been seriously challenged. The inconsistencies stemming from it are demonstrated and it is shown how they imply a legal design more preoccupied with traditional divisions of power and positions than with an interest in the reality of the people it is aimed at. In the article it is argued from within the best ingerest principle that the historical development neccessitates a re-thinking of the distinction between child welfare law and family law. It shows how the distinction is nationally and institutionally embedded. Further, that the distinction has only been superficially adressed by the CRC Committee.

  11. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    International Nuclear Information System (INIS)

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoSx (x?4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoSx under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS2 materials with very high pore volume and specific surface area, up to 0.45 cm3/g and 190 m2/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoSx particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS2 with very high porosity and surface area

  12. Digital Divide in Sub-Saharan African Universities: Recommendations and Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Barry, Boubakar; /Assoc. Afr. Univ.; Chukwuma, Victor; /Olabisi Onabanjo U.; Petitdidier, Monique; /CEPT, Velizy; Cottrell, Les; /SLAC; Bartons, Charles; /Australian Natl. U., RSES

    2009-12-17

    The Digital Divide prevents Africa from taking advantages of new information technologies. One of the most urgent priorities is to bring the Internet in African Universities, Research, and Learning Centers to the level of other regions of the world. eGY-Africa, and the Sharing Knowledge Foundation are two bottom-up initiatives by scientists to secure better cyber-infrastructure and Internet facilities in Africa. Recommendations by the present scientific communities are being formulated at national, regional and international levels. The Internet capabilities are well documented at country level overall, but this is not the case at the University level. The snapshot of the Internet status in universities in 17 African countries, obtained by a questionnaire survey, is consistent with measures of Internet penetration in the corresponding country. The monitoring of Internet performance has been proposed to those African universities to provide an information base for arguing the need to improve the coverage for Africa. A pilot program is recommended that will start scientific collaboration with Europe in western Africa using ICT. The program will lay the foundations for the arrival of new technologies like Grids.

  13. Mobile Phones Bridging the Digital Divide for Teens in the US?

    Directory of Open Access Journals (Sweden)

    Katie Brown

    2011-05-01

    Full Text Available In 2009, just 27% of American teens with mobile phones reported using their devices to access the internet. However, teens from lower income families and minority teens were significantly more likely to use their phones to go online. Together, these surprising trends suggest a potential narrowing of the digital divide, offering internet access to those without other means of going online. This is an important move, as, in today’s society, internet access is central to active citizenship in general and teen citizenship in particular. Yet the cost of this move toward equal access is absorbed by those who can least afford it: Teenagers from low income households. Using survey and focus group data from a national study of “Teens and Mobile Phone Use” (released by Pew and the University of Michigan in 2010, this article helps identify and explain this and other emergent trends for teen use (as well as non-use of the internet through mobile phones.

  14. Magnetized Water and Memory Meter

    OpenAIRE

    Ashraf Kotb

    2013-01-01

    This paper presents an experimental study to investigate the effect of using the magnetic water conditioner on the properties of water. The water flows through a closed loop, while the pH, TDS, and hardness represent its properties. For magnetic water conditioner with flux density of 170 mT, results showed that pH increased by 15.65% for 820 minutes of non-stop circulation. The increase in pH is divided to 93.5% for the first 360 minutes, and 6.5% for the last 460 minutes. TDS and Hardness of...

  15. Our Divided World: Poverty, Hunger & Overpopulation. Our Only Earth Series. A Curriculum for Global Problem Solving.

    Science.gov (United States)

    McKisson, Micki; MacRae-Campbell, Linda

    Both humanity and nature have suffered greatly from human insensitivity. Not only are the natural resources of the earth being depleted and its air, land and water polluted, the financial resources of humanity are being wasted on destructive expenditures. The "Our Only Earth" series is an integrated science, language arts, and social studies…

  16. Appraisal of the tight sands potential of the Sand Wash and Great Divide Basins

    International Nuclear Information System (INIS)

    The volume of future tight gas reserve additions is difficult to estimate because of uncertainties in the characterization and extent of the resource and the performance and cost-effectiveness of stimulation and production technologies. Ongoing R ampersand D by industry and government aims to reduce the risks and costs of producing these tight resources, increase the certainty of knowledge of their geologic characteristics and extent, and increase the efficiency of production technologies. Some basins expected to contain large volumes of tight gas are being evaluated as to their potential contribution to domestic gas supplies. This report describes the results of one such appraisal. This analysis addresses the tight portions of the Eastern Greater Green River Basin (Sand Wash and Great Divide Subbasins in Northwestern Colorado and Southwestern Wyoming, respectively), with respect to estimated gas-in-place, technical recovery, and potential reserves. Geological data were compiled from public and proprietary sources. The study estimated gas-in-place in significant (greater than 10 feet net sand thickness) tight sand intervals for six distinct vertical and 21 areal units of analysis. These units of analysis represent tight gas potential outside current areas of development. For each unit of analysis, a ''typical'' well was modeled to represent the costs, recovery and economics of near-term drilling prospects in that unit. Technically recoverable gas was calculated using reservoir properties and assumptions about current formation evaluation and extraction technology performance. Basin-specific capital and operating costs were incorporated along with taxes, royalties and current regulations to estimate the minimum required wellhead gas price required to make the typical well in each of unit of analysis economic

  17. Treatment of local recurrent breast cancer by divided dose electron beam radiation twice a week

    International Nuclear Information System (INIS)

    The objectives of this study were to investigate the effects of divided dose electron beam radiation twice a week (with a focal dose of 600 rads at a time) on local recurrent tumors of postoperative breast cancer and to compare it with the conventional photon radiation in the hope that it might be better tolerated by the patients, with less damage to normal skin and lung tissues. Out of 261 patients with breast cancer who came to the Department of Radiology, at Gunma Univ. Hospital, Maebashi, during the period Jan., 1970, through Jun., 1976, 41 patients who received electron beam radiation for local recurrence (in 81 sites) and 31 who received prophylactic radiation over the chest wall postoperatively. Tumors completely disappeared from 73 out of 81 sites irradiated for local recurrence (accounting 90% of the 81 sites). The local recurrent lesions were classified to the ''disseminated'' and the ''focal'' type to compare the effects of the radiation, and it was found that the radiation eliminated the tumors from all (100%) of the 63 sites of the former type, while the radiation was capable of eliminating the tumors from only 10 out of the 18 sites of the latter type (56%). When the focal type tumors were classified by histopathologic typing to compare the effects of the radiation, the radiation was assessed effective in papillotubular carcinoma, medullary tubular carcinoma and scirrhous carcinoma in the decreasing sequence of significance. Pulmonary disorders occurred in 12% of all the observed sites. However, it is possible to further reduce this incidence by the adequate use of the tissue compensating filter, Mix-R. A skin disorder (erosion) was observed in 59% of all the sites observed. However, it may be anticipated that the topical application of a suitable corticoid (Beta-methasone-17-valerate cream) preparation will by prophylactically effective. (auth.)

  18. Crossing the dividing surface of transition state theory. III. Once and only once. Selecting reactive trajectories.

    Science.gov (United States)

    Lorquet, J C

    2015-09-14

    The purpose of the present work is to determine initial conditions that generate reacting, recrossing-free trajectories that cross the conventional dividing surface of transition state theory (i.e., the plane in configuration space passing through a saddle point of the potential energy surface and perpendicular to the reaction coordinate) without ever returning to it. Local analytical equations of motion valid in the neighborhood of this planar surface have been derived as an expansion in Poisson brackets. We show that the mere presence of a saddle point implies that reactivity criteria can be quite simply formulated in terms of elements of this series, irrespective of the shape of the potential energy function. Some of these elements are demonstrated to be equal to a sum of squares and thus to be necessarily positive, which has a profound impact on the dynamics. The method is then applied to a three-dimensional model describing an atom-diatom interaction. A particular relation between initial conditions is shown to generate a bundle of reactive trajectories that form reactive cylinders (or conduits) in phase space. This relation considerably reduces the phase space volume of initial conditions that generate recrossing-free trajectories. Loci in phase space of reactive initial conditions are presented. Reactivity is influenced by symmetry, as shown by a comparative study of collinear and bent transition states. Finally, it is argued that the rules that have been derived to generate reactive trajectories in classical mechanics are also useful to build up a reactive wave packet. PMID:26374042

  19. Bridges across the Racial Digital Divide: Residential Ecology of Internet Use

    Directory of Open Access Journals (Sweden)

    Cao, Xingshan

    2008-01-01

    Full Text Available EnglishOur paper extends the study of residential ecology to understand social changes, specificallythe adoption of Internet use. We suggest that the residential ecology of the metropolitan area,in addition to household socioeconomic factors, should be considered in understanding Internetuse. The centripetal dimension of residential ecology, represented by residential isolationand the spatial concentration of the poor, and the centrifugal dimension of residential ecology,reflected by residential interaction of groups, are important to understanding the digitaldivide among racial groups. Based on the August 2000 Current Population Survey Computerand Internet Use Supplement, our results demonstrate that residential ecology is important tounderstanding the digital divide of groups, especially groups with low rates of Internet use,i.e., blacks and Hispanics. Implications are discussed.FrenchNotre article a étendu l’étude de l’écologie résidentielle dans le but de comprendre les changementssociaux; et spécialement l’adoption de l’utilisation d’internet. Nous suggérons quel’écologie résidentielle de la région métropolitaine, en outre des facteurs socioéconomiquesdes ménages, devrait être prise en compte pour comprendre l’utilisation d’internet. Nousavançons que la dimension centripète de l’écologie résidentielle, tel que représentée par l’isolationrésidentielle et la concentration spatiale des pauvres, ainsi que la dimension centrifugede l’écologie, tel que reflétée par l’interaction résidentielle entre les groupes, sont des facteursimportants pour comprendre la division numérique entre les groupes; et spécialement lesgroupes qui ont les taux d’utilisation les moins élevés, c’est-à-dire les noirs et les hispaniques.Les implications de ces faits sont discutées.

  20. European freshwater VHSV genotype Ia isolates divide into two distinct subpopulations

    DEFF Research Database (Denmark)

    Kahns, SØren; Skall, Helle Frank

    2012-01-01

    Viral haemorrhagic septicaemia (VHS), caused by the novirhabdovirus VHSV, often leads to significant economic losses to European rainbow trout production. The virus isolates are divided into 4 distinct genotypes with additional subgroups including sublineage Ia, isolates of which are the main source of outbreaks in European rainbow trout farming. A significant portion of Danish rainbow trout farms have been considered endemically infected with VHSV since the first disease outbreak was observed in the 1950s. However, following a series of sanitary programs starting in 1965, VHSV has not been detected in Denmark since January 2009. Full-length G-genes of all Danish VHSV isolates that were submitted for diagnostic analyses in the period 2004?2009 were sequenced and analysed. All 58 Danish isolates from rainbow trout grouped with sublineage Ia isolates. Furthermore, VHSV isolates from infected Danish freshwater catchments appear to have evolved into a distinct clade within sublineage Ia, herein designated clade Ia-1, whereas trout isolates originating from other continental European countries cluster in another distinct clade, designated clade Ia-2. In addition, phylogenetic analyses indicate that VHSV Ia-1 strains have caused a few outbreaks in Germany and the UK. It is likely that viruses have been transmitted from infected site(s) out of the Danish environment, although a direct transmission pathway has not been identified. Furthermore, VHSV Ia-2 isolates seem to have been transmitted to Denmark at least once. Interestingly, one viral isolate possibly persisted in a Danish watershed for nearly 4 yr without detection whereas other subclades of VHSV isolates appear to have been eliminated, probably because of implemented eradication procedures.

  1. A Socially-Just Internet: The Digital Divide, Cybercultural Agency, and Human Capabilities

    Directory of Open Access Journals (Sweden)

    David Toews

    2009-01-01

    Full Text Available This article argues that while modes of scholarship stressing structural insights into the digital divide and ethnographic insights into online communities each give us important information about current uses of the internet, for the sake of a unified social justice principle it is necessary to interpret these forms of knowledge in terms of what could be. Marx’s formula ‘the development of each as a condition for the development of all’ is put forward as the principle of a socially-just internet actualized from the ground up. It is argued that the most rapidly emerging and important form of constraint upon ‘the development of each’ is the for profit online social media industry in which moments of human communicative creativity become packaged as commodities for commercial purposes. Creative, cultural agency becomes an imposition rather than a liberation as represented in the industry ideology. It is argued therefore that groups that use the internet for serious play – the use of avatars in virtual worlds is discussed as an example – present us with a form of online subjectivity that is rising in importance as a form of cultural agency inasmuch as the play component is premised upon the rejection of pre-packaged forms of agency. Support for a socially-just internet would thus mean supporting the online communities formed in this process. Thus the argument is put forward that the importance of serious online play groups is not due to their potential for forming communities per se but is rather due to their potential for resisting the imposition of agency. Inasmuch as online communities in the midst of such groups can bolster that goal, they can represent the development of human capabilities in a way that expands the theme of social justice.

  2. A narrow band-pass filter type Wilkinson power divider for I-Q demodulator in microwave interferometer system

    Science.gov (United States)

    Wang, X.; Yoshikawa, M.; Kohagura, J.; Shima, Y.; Ikezoe, R.; Sakamoto, M.; Imai, T.; Nakashima, Y.; Ma, Z.; Sakagami, I.; Mase, A.

    2015-11-01

    I-Q (In-phase Quadrature) demodulator is one of key components in microwave interferometer system application. Normally, I-Q demodulator consists of amplifiers, mixers, 90 degree phase shifter, power divider and band-pass filters, and it is widely used in various microwave communication systems and measurement systems. In this paper, power divider and band-pass filters are newly designed as one single passive component, therefore, I-Q demodulator topology becomes simplified. The novel narrow band-pass filter type Wilkinson power divider not only provides extremely miniaturized circuit size, but also maintains the band-pass filter performance and power division function as well. One experimental circuit shows good agreement with the theoretical simulation.

  3. Gender Digital Divide: Comparative Assessment of the Information Communications Technologies and Literacy Levels of Students in Nigeria

    Directory of Open Access Journals (Sweden)

    Onyenekenwa Cyprian Eneh

    2010-01-01

    Full Text Available The Information Communications Technologies (ICTs are driving development. Their adoption and integration has become imperative for national development. This study investigated for comparison the ICTs literacy levels of boy and girl-students of senior secondary Grade III in Nigeria, using Enugu State as the case study. Although, ICTs literacy levels were generally poor, the boy-students were better all-round than the girl-students in ICTs literacy parameters tested, namely, ability to process words, access the web for browsing and managing web contents, thereby establishing existence of gender digital divide in the system. The implications of the poor literacy levels and the observed gender digital divide for development were given and recommendations were proffered for narrowing the divide.

  4. "Sleeping with the Enemy": How Far Are You Prepared to Go to Make a Difference? A Look at the Divide between Academic and Allied Staff

    Science.gov (United States)

    Wohlmuther, Sue

    2008-01-01

    There have been a number of papers written about the academic-allied staff divide within educational institutions in the Western world. This paper considers one particular institution to ascertain whether there is evidence of a divide and, if there is, whether there are other factors that influence the perception of a divide; for example, length…

  5. Human Development report 2007/2008 - Fighting climate change: human solidarity in a divided world

    International Nuclear Information System (INIS)

    Climate change is the defining human development challenge of the 21. Century. Failure to respond to that challenge will stall and then reverse international efforts to reduce poverty. The poorest countries and most vulnerable citizens will suffer the earliest and most damaging setbacks, even though they have contributed least to the problem. Looking to the future, no country - however wealthy or powerful - will be immune to the impact of global warming. The Human Development Report 2007/2008 shows that climate change is not just a future scenario. Increased exposure to droughts, floods and storms is already destroying opportunity and reinforcing inequality. Meanwhile, there is now overwhelming scientific evidence that the world is moving towards the point at which irreversible ecological catastrophe becomes unavoidable. Business-as-usual climate change points in a clear direction: unprecedented reversal in human development in our lifetime, and acute risks for our children and their grandchildren. There is a window of opportunity for avoiding the most damaging climate change impacts, but that window is closing: the world has less than a decade to change course. Actions taken - or not taken - in the years ahead will have a profound bearing on the future course of human development. The world lacks neither the financial resources nor the technological capabilities to act. What is missing is a sense of urgency, human solidarity and collective interest. As the Human Development Report 2007/2008 argues, climate change poses challenges at many levels. In a divided but ecologically interdependent world, it challenges all people to reflect upon how we manage the environment of the one thing that we share in common: planet Earth. It challenges us to reflect on social justice and human rights across countries and generations. It challenges political leaders and people in rich nations to acknowledge their historic responsibility for the problem, and to initiate deep and early cuts in greenhouse gas emissions. Above all, it challenges the entire human community to undertake prompt and strong collective action based on shared values and a shared vision

  6. On the progress of a water calorimeter project for the verification of radiotherapy dosimetry

    International Nuclear Information System (INIS)

    A sealed water calorimeter has been constructed at the department of radiation physics in Malmoe, Sweden with support from the Swedish Radiation Protection Authority. The calorimeter follows the design of the NRC sealed water calorimeter. The temperature increase during irradiation is measured with two thermistor probes in the centre of a sealed cylindrical glass vessel. The sealed glass vessel contains high purity water and is positioned in a large water phantom to measure the absorbed dose to water. In the present design, the water phantom is thermally isolated from the environment and operated at 4 deg. C to reduce the problem associated with convective heat transfer. The thermal isolation is achieved by enclosing the water phantom in a wooden box (92x92x85 cm3) lined with 6 cm of Styrofoam. The temperature in the wooden box is kept at 4 deg. C by circulating air, cooled when passing a heat exchanger coupled to a thermostated bath. Since a detailed knowledge of the absolute temperature is not required for calorimetry, the main requirement is that the two thermistor probes accurately measure temperature changes. The thermistor probes are calibrated against platinum resistance probes, traceable to the Swedish national temperature standard. When preparing for measurements, the glass vessel is first filled with high purity water and then bubbled with N2 gas for one to two hours. After the gas bubbling, the position of the thermistor probes is adjusted and the glass vessel is suspended in the water phantom. The probes are connected to a four-arm AC bridge, where two of the other arms consist of high precision resistors (10k? each), and the third arm includes a decade resistor box for balancing the bridge. The output voltage is measured with a commercial lock-in amplifier. Platinum resistor probes, used to monitor the temperature in the water phantom and in the air volume inside the wooden box, are connected to a Keithley 2001 multimeter equipped with a scanner card. The multimeter, lock-in amplifier, and bridge balancing resistor decade are all connected to a portable PC using a GPIB interface card. This allows each of the devices to be controlled and read out remotely using software developed at NRC. The software allows the bridge to be balanced, the characteristics of the lock-in amplifier to be changed, and controls the acquisition of data according to a pre-selected scheme. It is also used for calculation of the absorbed dose from the measured voltage drop after an irradiation. The sealed water calorimeter is intended to be used in clinical photon, electron, and proton beams to determine experimentally kQ,Qo factors for a variety of ionisation chambers. These factors are fundamental when implementing the new international Code of Practice for radiotherapy dosimetry. The measured values will be compared with the theoretical factors in TRS-398

  7. Are Children's Memory Illusions Created Differently from Those of Adults? Evidence from Levels-of-Processing and Divided Attention Paradigms

    Science.gov (United States)

    Wimmer, Marina C.; Howe, Mark L.

    2010-01-01

    In two experiments, we investigated the robustness and automaticity of adults' and children's generation of false memories by using a levels-of-processing paradigm (Experiment 1) and a divided attention paradigm (Experiment 2). The first experiment revealed that when information was encoded at a shallow level, true recognition rates decreased for…

  8. Image-based focused counting of dividing cells for non-invasive monitoring of regenerative medicine products.

    Science.gov (United States)

    Sasaki, Kei; Miyata, Hirofumi; Sasaki, Hiroto; Kang, Siu; Yuasa, Tetsuya; Kato, Ryuji

    2015-11-01

    Despite the growing numbers of successful applications in regenerative medicine, biotechnologies for evaluating the quality of cells remain limited. To evaluate the cultured cells non-invasively, image-based cellular assessment method holds great promise. However, although there are various image-processing algorithms, very few studies have focused to prove the effectiveness of phase contrast images with risk assessment example that reflects actual difficulties in regenerative medicine products. In this study, we developed a simple image-processing method to recognize the number of dividing cells in time-course phase-contrast microscopic images, and applied this method to assess the irregular proliferation behavior in normal cells. Practically, as a model, rapid proliferating human fibrosarcoma cells were mixed in normal human fibroblasts in the same culture dish, and their sarcoma existence was evaluated. As a result, the existence of sarcoma population in normal cell sample could be feasibly detected within earliest period of cell culture by their irregular rise of accumulated counts of dividing cells. Our image-processing technique also illustrates the technical effectiveness of combining intra-frame and inter-frame image processing to accurately count only the dividing cells. Our concept of focused counting of dividing cells shows a successful example of image-based analysis to quickly and non-invasively monitor the regular state of regenerative medicine products. PMID:25921220

  9. Research on Motivation in Collaborative Learning: Moving beyond the Cognitive-Situative Divide and Combining Individual and Social Processes

    Science.gov (United States)

    Jarvela, Sanna; Volet, Simone; Jarvenoja, Hanna

    2010-01-01

    In this article we propose that in order to advance our understanding of motivation in collaborative learning we should move beyond the cognitive-situative epistemological divide and combine individual and social processes. Our claim is that although recent research has recognized the importance of social aspects in emerging and sustained…

  10. Chinese hamster ovary cell performance enhanced by a rational divide-and-conquer strategy for chemically defined medium development.

    Science.gov (United States)

    Liu, Yaya; Zhang, Weiyan; Deng, Xiancun; Poon, Hong Fai; Liu, Xuping; Tan, Wen-Song; Zhou, Yan; Fan, Li

    2015-12-01

    Basal medium design is considered one of the most important steps in process development. To optimize chemically defined (CD) media efficiently and effectively for the biopharmaceutical industry, a two-step rational strategy was applied to optimize four antibody producing Chinese hamster ovary (CHO) cell lines. In the first step, 48 of 52 components of our in-house medium were divided into three groups according to their characteristics. In the next step, these groups were optimized by spent medium analysis, response surface methodology and mixture design. Because these steps in our strategy involved dividing medium components into groups and subsequently adjusting the concentration of the components, we termed this medium development strategy "divide and conquer". By applying the strategy, we were able to improve the titers of CHO-S, CHO-DG44 and two CHO-K1 cell lines 1.92, 1.86, 2.92 and 1.62-fold, respectively, in 8 weeks with fewer than 60 tests. This divide-and-conquer strategy was efficient, effective, scalable and universal in our current study and offered a new approach to CD media development. PMID:26183860

  11. Spatial and temporal variability of snow accumulation rate on the East Antarctic ice divide between Dome Fuji and EPICA DML

    Directory of Open Access Journals (Sweden)

    S. Fujita

    2011-11-01

    Full Text Available To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML, East Antarctica, a 2800-km-long Japanese-Swedish traverse was carried out. The route includes ice divides between two ice-coring sites at Dome Fuji and EPICA DML. We determined the surface mass balance (SMB averaged over various time scales in the late Holocene based on studies of snow pits and firn cores, in addition to radar data. We find that the large-scale distribution of the SMB depends on the surface elevation and continentality, and that the SMB differs between the windward and leeward sides of ice divides for strong-wind events. We suggest that the SMB is highly influenced by interactions between the large-scale surface topography of ice divides and the wind field of strong-wind events that are often associated with high-precipitation events. Local variations in the SMB are governed by the local surface topography, which is influenced by the bedrock topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by ~15 % than averages over longer periods of 722 a or 7.9 ka before AD 2008. A similar increasing trend has been reported for many inland plateau sites in Antarctica with the exception of several sites on the leeward side of the ice divides.

  12. Divided Attention Can Enhance Early-Phase Memory Encoding: The Attentional Boost Effect and Study Trial Duration

    Science.gov (United States)

    Mulligan, Neil W.; Spataro, Pietro

    2015-01-01

    Divided attention during encoding typically produces marked reductions in later memory. The attentional boost effect (ABE) is a surprising variation on this phenomenon. In this paradigm, each study stimulus (e.g., a word) is presented along with a target or a distractor (e.g., different colored circles) in a detection task. Later memory is better…

  13. "Is There a Second Level Divide in Student’s Internet Skills? :  A Cross-Country Analysis of Denmark & India

    DEFF Research Database (Denmark)

    Dau, Susanne; Purushothaman, Aparna

    2015-01-01

    The concept of digital divide have moved beyond physical disparities in usage and also encompasses issues impending access like human (skills) social, cultural, and psychological barriers that affect the usage of existing available technologies apart from ownership. This paper focuses on the insufficient level of skills which students have in making the best use of available Internet technology. Varying online skills of the students in higher education from two countrywide scenarios - Denmark and India are discussed. The paper emphasizes on the reflective and conceptual issues which the students face to take information from the Internet that brings a second level of divide. Through a cross-national comparison the paper hopes to contribute to the literature to learn from each other´s experiences and giving insights to researchers on digital divide. The digital divide in Internet skills is illuminated from different perspectives in the context of two countries which has contrasting socio-economic environment, ICT development and network connectivity. The paper´s brings insights on how different types of literacy skills influence students successful access to relevant online learning and knowledge retrievement.

  14. USGS water summary

    Science.gov (United States)

    The U.S. Geo1ogical:Survey has recently published a valuable source document for all interested in water resources topics. The “National Water Summary” is divided into three parts. The first, Selected Hydrologic Events for Water Year 1984, provides a synopsis of hydrologic conditions and water-related events that occurred between August 1983 and September 1984. Streamflow variations are compared to precipitation, temperature, and upper-air atniospheric pressure for the four seasonal quarters of the year, so that the relation of surface water flows to climatic conditions can clearly be seen. The second section, Hydrologic Perspectives on Water Issues, presents an analysis of the occurrence of nitrate in groundwater, an explanation of groundwater level declines in selected areas of the country that represent different hydrogeologic environments, and discussions of the distribution and trends of phosphorous, dissolved solids, suspended sediment, and inorganic nitrogen in major rivers. The final part, State Summaries of Groundwater Resources, summarizes the distribution, characteristics, and uses of principal aquifers for each state, the District of Columbia, Puerto Rico, the U.S. Virgin Islands, the Trust Territory of the Pacific Islands, Saipan, Guam, and American Samoa. Each summary contains multicolor maps that show the locations of the aquifers and major areas of groundwater withdrawal, hydrographs that show trends in water levels, arrd tables that describe the characteristics of the aquifers and present data on groundwater withdrawals. The state agencies, laws, and iegulatioris that are involved in groundwater management are also described.

  15. Room-temperature antiferromagnetic memory resistor.

    Czech Academy of Sciences Publication Activity Database

    Martí, Xavier; Fina, I.; Frontera, C.; Liu, J.; Wadley, P.; He, P.; Paull, R.J.; Clarkson, J.D.; Kudrnovský, Josef; Turek, Ilja; Kuneš, Jan; Yi, D.; Chu, J.-H.; Nelson, C.T.; You, L.; Arenholz, E.; Salahuddin, S.; Fontcuberta, J.; Jungwirth, Tomáš; Ramesh, R.

    2014-01-01

    Ro?. 13, ?. 4 (2014), s. 367-374. ISSN 1476-1122 R&D Projects: GA MŠk(CZ) LM2011026; GA ?R(CZ) GAP204/11/1228 Grant ostatní: ERC Advanced Grant 0MSPIN(XE) 268066; AV ?R(CZ) Premium Academiae Institutional support: RVO:68378271 ; RVO:68081723 Keywords : spintronics * antiferromagnets * memories Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 36.503, year: 2014

  16. Water cooled nuclear reactor

    International Nuclear Information System (INIS)

    The pressure vessel is divided by a transverse separating wall above the core into a high pressure and a low pressure plenum chamber. The cooling water flows vertically from below upwards through the core, so that hydraulic lifting forces act on the core. To compensate for these forces a core holding down device, consisting of a pressure piston system is provided. The piston surface is at the pressure of the upper high pressure plenum chamber, while the piston rod acts through the separating wall inside a sealing cylinder on the fuel elements in the core. (DG)

  17. The digital divide: Differences in computer use between home and school in low socio-economic households.

    Directory of Open Access Journals (Sweden)

    Sutherland-Wmith, W.

    2003-01-01

    Full Text Available This article examines information and communication technologies (ICTs practices in the home and school settings of four disadvantaged families. It reports the findings of a year-long study that investigated the nexus between computer-mediated literacy practices at home and at school and whether this inter-connectivity could make a difference in school success. The findings indicate that there was disjunction between home and school use. The “digital divide” exists for the families of this study, not in terms of access but in the gap between ICT practices at home and school. Schools in this study did not integrate ICT skills learned and demonstrated in the home environment into ICT practices at school. The study concludes that constructing pedagogical connections between home and school ICT practices may begin to bridge the “digital divide”.

  18. Two-phase refrigerant distribution in a parallel flow minichannel heat exchanger having lower combining/dividing header

    Science.gov (United States)

    Byun, Ho-Won; Kim, Nae-Hyun

    2015-10-01

    R-410A distribution in a two pass evaporator with lower horizontal combining-dividing header was investigated. Tubes were heated to yield a test section outlet superheat of 5 °C with inlet quality of 0.2. The number of tubes was ten for the inlet pass and 12 or 14 for the outlet pass. For each case, mass flux was varied from 73 to 143 kg/m2 s. In the combining/dividing header, two-phase mixture out of the inlet pass is first merged and then re-distributed to the outlet pass. More liquid is forced downstream as mass flux or quality increases Effect of insertion device in the inlet header was also investigated. Efforts were made to develop correlations to predict the liquid or gas distribution in a header with limited success. Header pressure drop data are also provided.

  19. Analysis of Multi-Loop Control Structures of Dividing-Wall Distillation Columns Using a Fundamental Model

    Directory of Open Access Journals (Sweden)

    Salvador Tututi-Avila

    2014-02-01

    Full Text Available Dividing-wall columns (DWCs have significant potential as energy-efficient processes for the separation of multicomponent mixtures. However, in addition to an efficient steady state design, dynamics and control also play a major part for the success of a technology. This is especially so for complex distillation systems. This paper investigates the dynamics of a dividing wall column used for the separation of ternary mixtures. A detailed dynamic first principles-based model of the column I s developed in gPROMS. The model is used to generate data used for control loop pairing via the Relative Gain Array (RGA, and controller parameters are found by using Internal Model Control (IMC tuning. The best control structures for DWC systems, involving four different ternary mixtures, and two different feed compositions for each mixture, are investigated.

  20. A Wilkinson Power Divider with Harmonic Suppression and Size Reduction using High-low Impedance Resonator Cells

    Directory of Open Access Journals (Sweden)

    M. Hayati

    2015-04-01

    Full Text Available A miniaturized Wilkinson power divider using high-low impedance resonator cells are designed and fabricated. The proposed power divider occupies 23.7% of the conventional structure circuit area at the operating frequency of 0.9 GHz and it is also able to suppress harmonics. According to the measured results at 0.9 GHz, the insertion-losses of output ports are 3.087 dB, the return-losses at all ports are more than 30 dB, and the isolation between output ports is better than 35 dB. Also, 2nd to 10th spurious frequencies are suppressed. According to the measured S11, when it is less than -15 dB (from 0.65 GHz to 1.1 GHz the fractional bandwidth of the proposed structure is 50%. Good agreement between simulation and measured results is achieved.

  1. Water And Waste Water Processing

    International Nuclear Information System (INIS)

    This book shows US the distribution diagram of water and waste water processing with device of water processing, and device of waste water processing, property of water quality like measurement of pollution of waste water, theoretical Oxygen demand, and chemical Oxygen demand, processing speed like zero-order reactions and enzyme reactions, physical processing of water and waste water, chemical processing of water and waste water like neutralization and buffering effect, biological processing of waste water, ammonia removal, and sludges processing.

  2. Bridging the Divide: Linking Genomics to Ecosystem Responses to Climate Change: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Melinda D.

    2014-03-15

    Over the project period, we have addressed the following objectives: 1) assess the effects of altered precipitation patterns (i.e., increased variability in growing season precipitation) on genetic diversity of the dominant C4 grass species, Andropogon gerardii, and 2) experimentally assess the impacts of extreme climatic events (heat wave, drought) on responses of the dominant C4 grasses, A. gerardii and Sorghastrum nutans, and the consequences of these response for community and ecosystem structure and function. Below is a summary of how we have addressed these objectives. Objective 1 After ten years of altered precipitation, we found the number of genotypes of A. gerardii was significantly reduced compared to the ambient precipitation treatments (Avolio et al., 2013a). Although genotype number was reduced, the remaining genotypes were less related to one another indicating that the altered precipitation treatment was selecting for increasingly dissimilar genomes (based on mean pairwise Dice distance among individuals). For the four key genotypes that displayed differential abundances depending on the precipitation treatment (G1, G4, and G11 in the altered plots and G2 in the ambient plots), we identified phenotypic differences in the field that could account for ecological sorting (Avolio & Smith, 2013a). The three altered rainfall genotypes also have very different phenotypic traits in the greenhouse in response to different soil moisture availabilities (Avolio and Smith, 2013c). Two of the genotypes that increased in abundance in the altered precipitation plots had greater allocation to root biomass (G4 and G11), while G1 allocated more biomass aboveground. These phenotypic differences among genotypes suggests that changes in genotypic structure between the altered and the ambient treatments has likely occurred via niche differentiation, driven by changes in soil moisture dynamics (reduced mean, increased variability and changes in the depth distribution of soil moisture) under a more variable precipitation regime, rather than reduced population numbers (A. gerardii tiller densities did not differ between altered and ambient treatments; p = 0.505) or a priori differences in genotype richness (Avolio et al.2013a). This ecological sorting of genotypes, which accounts for 40% of all sampled individuals in the altered plots, is an important legacy of the press chronic climate changes in the RaMPs experiment. Objective 2 In May 2010, we established the Climate Extremes Experiment at the Konza Prairie Biological Station. For the experiment, a gradient of temperatures, ranging from ambient to extreme, were imposed in 2010 and 2011 as a mid-season heat wave under well-watered or severe drought conditions. This study allowed us for the first time to examine species-specific thresholds of responses to climate extremes and assess how these phenotypic responses may impact selection of particular genotypes, with the ultimate goal of linking alterations in individual performance and genetic diversity to ecosystem structure and functioning. We found that tallgrass prairie was resistant to heat waves, but it was not resistant to extreme drought, which reduced aboveground net primary productivity (ANPP) below the lowest level measured in this grassland in almost thirty years (Hoover et al. in press(a)). This extreme reduction in ecosystem function was a consequence of reduced productivity of both C4 grasses and C3 forbs. This reduction in biomass of the C4 grasses (Andropogon gerardii and Sorghastrum nutans) was, in part, due to significant reductions in photosynthesis, leaf water potential and productivity with drought in the dominant grasses species, with S. nutans was more sensitive than A. gerardii to drought (Hoover et al. in press(b)). However, the dominant forb was negatively impacted by the drought more than the dominant grasses, and this led to a reordering of species abundances within the plant community. Although this change in community composition persisted post-drought, ANPP recovered completely the year after drought

  3. Dividing phases in two-phase flow and modeling of interfacial drag

    Energy Technology Data Exchange (ETDEWEB)

    Narumo, T.; Rajamaeki, M. [VTT Energy (Finland)

    1997-07-01

    Different models intended to describe one-dimensional two-phase flow are considered in this paper. The following models are introduced: conventional six-equation model, conventional model equipped with terms taking into account nonuniform transverse velocity distribution of the phases, several virtual mass models and a model in which the momentum equations have been derived by using the principles of Separation of the Flow According to Velocity (SFAV). The dynamics of the models have been tested by comparing their characteristic velocities to each other and against experimental data. The results show that the SFAV-model makes a hyperbolic system and predicts the propagation velocities of disturbances with the same order of accuracy as the best tested virtual mass models. Furthermore, the momentum interaction terms for the SFAV-model are considered. These consist of the wall friction terms and the interfacial friction term. The authors model wall friction with two independent terms describing the effect of each fluid on the wall separately. In the steady state, a relationship between the slip velocity and friction coefficients can be derived. Hence, the friction coefficients for the SFAV-model can be calculated from existing correlations, viz. from a drift-flux correlation and a wall friction correlation. The friction model was tested by searching steady-state distributions in a partial BWR fuel channel and comparing the relaxed values with the drift-flux correlation, which agreed very well with each other. In addition, response of the flow to a sine-wave disturbance in the water inlet flux was calculated as function of frequency. The results of the models differed from each other already with frequency of order 5 Hz, while the time constant for the relaxation, obtained from steady-state distribution calculation, would have implied significant differences appear not until with frequency of order 50 Hz.

  4. After continents divide: Comparative phylogeography of reef fishes from the Red Sea and Indian Ocean

    KAUST Repository

    Dibattista, Joseph D.

    2013-01-07

    Aim: The Red Sea is a biodiversity hotspot characterized by a unique marine fauna and high endemism. This sea began forming c. 24 million years ago with the separation of the African and Arabian plates, and has been characterized by periods of desiccation, hypersalinity and intermittent connection to the Indian Ocean. We aim to evaluate the impact of these events on the genetic architecture of the Red Sea reef fish fauna. Location: Red Sea and Western Indian Ocean. Methods: We surveyed seven reef fish species from the Red Sea and adjacent Indian Ocean using mitochondrial DNA cytochrome c oxidase subunit I and cytochrome b sequences. To assess genetic variation and evolutionary connectivity within and between these regions, we estimated haplotype diversity (h) and nucleotide diversity (?), reconstructed phylogenetic relationships among haplotypes, and estimated gene flow and time of population separation using Bayesian coalescent-based methodology. Results: Our analyses revealed a range of scenarios from shallow population structure to diagnostic differences that indicate evolutionary partitions and possible cryptic species. Conventional molecular clocks and coalescence analyses indicated time-frames for divergence between these bodies of water ranging from 830,000 years to contemporary exchange or recent range expansion. Colonization routes were bidirectional, with some species moving from the Indian Ocean to the Red Sea compared with expansion out of the Red Sea for other species. Main conclusions: We conclude that: (1) at least some Red Sea reef fauna survived multiple salinity crises; (2) endemism is higher in the Red Sea than previously reported; and (3) the Red Sea is an evolutionary incubator, occasionally contributing species to the adjacent Indian Ocean. The latter two conclusions - elevated endemism and species export - indicate a need for enhanced conservation priorities for the Red Sea. © 2013 Blackwell Publishing Ltd.

  5. Dividing phases in two-phase flow and modeling of interfacial drag

    International Nuclear Information System (INIS)

    Different models intended to describe one-dimensional two-phase flow are considered in this paper. The following models are introduced: conventional six-equation model, conventional model equipped with terms taking into account nonuniform transverse velocity distribution of the phases, several virtual mass models and a model in which the momentum equations have been derived by using the principles of Separation of the Flow According to Velocity (SFAV). The dynamics of the models have been tested by comparing their characteristic velocities to each other and against experimental data. The results show that the SFAV-model makes a hyperbolic system and predicts the propagation velocities of disturbances with the same order of accuracy as the best tested virtual mass models. Furthermore, the momentum interaction terms for the SFAV-model are considered. These consist of the wall friction terms and the interfacial friction term. The authors model wall friction with two independent terms describing the effect of each fluid on the wall separately. In the steady state, a relationship between the slip velocity and friction coefficients can be derived. Hence, the friction coefficients for the SFAV-model can be calculated from existing correlations, viz. from a drift-flux correlation and a wall friction correlation. The friction model was tested by searching steady-state distributions in a partial BWR fuel channel and comparing the relaxed values with the drift-flux correlation, which agreed very well with each other. In addition, response of the flow to a sine-wave disturbance in the water inlet flux was calculated as function of frequency. The results of the models differed from each other already with frequency of order 5 Hz, while the time constant for the relaxation, obtained from steady-state distribution calculation, would have implied significant differences appear not until with frequency of order 50 Hz

  6. The Model of Lake Operation in Water Transfer Projects Based on the Theory of Water- right

    Science.gov (United States)

    Bi-peng, Yan; Chao, Liu; Fang-ping, Tang

    the lake operation is a very important content in Water Transfer Projects. The previous studies have not any related to water-right and water- price previous. In this paper, water right is divided into three parts, one is initialization waterright, another is by investment, and the third is government's water- right re-distribution. The water-right distribution model is also build. After analyzing the cost in water transfer project, a model and computation method for the capacity price as well as quantity price is proposed. The model of lake operation in water transfer projects base on the theory of water- right is also build. The simulation regulation for the lake was carried out by using historical data and Genetic Algorithms. Water supply and impoundment control line of the lake was proposed. The result can be used by south to north water transfer projects.

  7. Inequality in new global governance arrangements: the North South Divide in city networks for global environmental governance

    OpenAIRE

    Bouteligier, S.

    2011-01-01

    Networks are often portrayed as more equal governance arrangements. Their horizontal character easily leads to the assumption that they go beyond traditional divides. Power relations within networks are neglected because the collaborative activities receive the bulk of attention. However, from a critical reading of the network and flows literature we know that networks are not free of power relations, and that they create new inequalities and sometimes even intensify existing ones. Increasing...

  8. The Supply Side of the Digital Divide: Is There Equal Availability in the Broadband Internet Access Market?

    OpenAIRE

    Prieger, James E.

    2002-01-01

    The newest dimension of the Digital Divide is access to broadband (high-speed) Internet service. Using comprehensive U.S. data covering all forms of access technology (chiefly DSL and cable modem), I look for evidence of unequal broadband availability in areas with high concentrations of poor, minority, or rural households. There is little evidence of unequal availability based on income or on black or Hispanic concentration. There is mixed evidence concerning availability based on Native Ame...

  9. TRAPPII is required for cleavage furrow ingression and localization of Rab11 in dividing male meiotic cells of Drosophila

    OpenAIRE

    Carmen C. Robinett; Giansanti, Maria Grazia; Gatti, Maurizio; Fuller, Margaret T.

    2009-01-01

    Although membrane addition is crucial for cytokinesis in many animal cell types, the specific mechanisms supporting cleavage furrow ingression are not yet understood. Mutations in the gene brunelleschi (bru), which encodes the Drosophila ortholog of the yeast Trs120p subunit of TRAPPII, cause failure of furrow ingression in male meiotic cells. In non-dividing cells, Brunelleschi protein fused to GFP is dispersed throughout the cytoplasm and enriched at Golgi organelles...

  10. Metabolic Profiling of Dividing Cells in Live Rodent Brain by Proton Magnetic Resonance Spectroscopy (1HMRS) and LCModel Analysis

    DEFF Research Database (Denmark)

    Park, June-Hee; Lee, Hedok; Makaryus, Rany; Yu, Mei; Smith, S David; Sayed, Kasim; Feng, Tian; Holland, Eric; Van der Linden, Annemie; Bolwig, Tom G; Enikolopov, Grigori; Benveniste, Helene

    2014-01-01

    RATIONALE: Dividing cells can be detected in the live brain by positron emission tomography or optical imaging. Here we apply proton magnetic resonance spectroscopy (1HMRS) and a widely used spectral fitting algorithm to characterize the effect of increased neurogenesis after electroconvulsive shock in the live rodent brain via spectral signatures representing mobile lipids resonating at ?1.30 ppm. In addition, we also apply the same 1HMRS methodology to metabolically profile glioblastomas with ...

  11. Dividing the spoils of growth and the cell cycle: The fission yeast as a model for the study of cytokinesis.

    OpenAIRE

    Goyal, Anupama; Takaine, Masak; Simanis, Viesturs; Nakano, Kentaro

    2011-01-01

    Cytokinesis is the final stage of the cell cycle, and ensures completion of both genome segregation and organelle distribution to the daughter cells. Cytokinesis requires the cell to solve a spatial problem (to divide in the correct place, orthogonally to the plane of chromosome segregation) and a temporal problem (to coordinate cytokinesis with mitosis). Defects in the spatiotemporal control of cytokinesis may cause cell death, or increase the risk of tumor formation [Fujiwara et al., 2005 (...

  12. Performance Effects of Nicotine during Selective Attention, Divided Attention, and Simple Stimulus Detection: An fMRI Study

    OpenAIRE

    Hahn, Britta; Ross, Thomas J; Wolkenberg, Frank A.; Shakleya, Diaa M.; HUESTIS, MARILYN A.; Stein, Elliot A.

    2008-01-01

    Attention-enhancing effects of nicotine appear to depend on the nature of the attentional function. Underlying neuroanatomical mechanisms, too, may vary depending on the function modulated. This functional magnetic resonance imaging study recorded blood oxygen level–dependent (BOLD) activity in minimally deprived smokers during tasks of simple stimulus detection, selective attention, or divided attention after single-blind application of a transdermal nicotine (21 mg) or placebo patch. Smoker...

  13. Cutting the mists of the Black Mountain : cleavages in Montenegro’s divide over statehood and identity

    OpenAIRE

    DZANKIC, Jelena

    2013-01-01

    The two decades of Montenegro's transition that followed the disintegration of Yugoslavia were marked by the transformation of the ambitions of the ruling political elites, which pushed the republic that once sought to be a member in a federal state towards independence. The shift in the agendas of the political elites also changed the meaning of the notions of “Montenegrin” and “Serb”. Hence, this paper looks at the cleavages that emerged during Montenegro's divide over statehood and identit...

  14. When two hands rock the cradle : symbolic dimensions of the divide over statehood and identity in Montenegro

    OpenAIRE

    DZANKIC, Jelena

    2014-01-01

    The most manifest result of the divide over statehood that consumed Montenegro’s politics over the past decade has been the change in the meaning of national categories. In the political discourse, and subsequently in the public sphere, being a ‘Montenegrin’ became associated with the restoration of Montenegro’s sovereignty, while being a ‘Serb’ (in Montenegro) was related to the preservation of the common state with Serbia. Rather than being an endogenously induced identity change, the recon...

  15. The divide-and-conquer and employer/employee models of discrimination: neoclassical competition as a familial defect

    OpenAIRE

    Mason, Patrick L.

    1992-01-01

    This article is an examination of the similarities between Michael Reich’s divide-and-conquer model of discrimination and the Becker-Arrow taste model of discrimination. It shows that Reich’s model of discrimination is analytically identical to Arrow’s employer discrimination model when employer utility is a function of total profits and the racial employment ratio. It also shows that the Becker-Arrow distinction between employer and employee discrimination is invalid. Finally, the author arg...

  16. Three-month water degradation of resin-dentin interfaces subjected to direct and indirect exposure

    OpenAIRE

    Abuna, Gabriel; Felizardo, Klissia R.; Bacchi, Atais; Correr-Sobrinho, Lourenço; Sinhoreti, Mario Alexandre; Correr, Americo; Feitosa, Victor Pinheiro

    2014-01-01

    Objectives: The aim of this study was to assess the effects direct or indirect water exposure on the 3 months hydrolytic degradation of three dentin bonding agents. Materials and methods: The samples were divided in three groups: Clearfil SE Bond, Clearfil S3, Adper Singlebond 2; and the samples were restored with Filtek Z350. Subsequent to the restorative procedures, the specimens of each group were divided into three subgroups (immersed in water deionised): Control (24h-37ºC), Direct Water ...

  17. Digital Divides Revisited:A Process View of the Acquisitions of Information and Communication Technology(ICTSkills by the Elderly

    Directory of Open Access Journals (Sweden)

    Yi-Hsuan Lin

    2009-06-01

    Full Text Available This paper explores the process of information and communication technology (ICT skill acquisition by senior citizens. Its aim is to explore the successes and problems of such endeavors, and to rethink the age-related digital divide issue. This paper first reviews literature relating to the digital divide, especially issues concerning ICT skill acquisition by senior citizens. The paper then reports an empirical study on this topic and concludes that three factors-age-related issues, the necessity of acquiring specific skills for ICT usage, and pre-adjustments in ICT targeting younger people-create barriers for acquisition of ICT skills by older people. Comprehensive and immediate social support may help older people bridge the barriers, however. Moreover, with particular regard to the digital divide, those who provide services to the elderly should not only focus on content delivery and resources, but thoroughly reconsider their methods as well. Understanding the interests and needs of older people as well as assessing available social support may help the elderly acquire ICT skills more successfully. Devising suitable curricula and securing social support outside the family can therefore be crucial.

  18. Death with "dignity": the wedge that divides the disability rights movement from the right to die movement.

    Science.gov (United States)

    Behuniak, Susan M

    2011-01-01

    Much of the American debate over physician assisted death (PAD) is framed as an ideological split between conservatives and liberals, pro life and pro choice advocates, and those who emphasize morality versus personal autonomy. Less examined, but no less relevant, is a split within the ranks of progressives--one that divides those supporting a right to die in the name of human rights from disability rights activists who invoke human rights to vehemently oppose euthanasia. This paper reviews how "dignity" serves both as a divisive wedge in this debate but also as a value that can span the divide between groups and open the way to productive discourse. Supporters of legalized euthanasia use "dignity" to express their position that some deaths might indeed be accelerated. At the same time, opponents adopt the concept to argue that physician assisted suicide stigmatizes life with a disability. To bridge this divide, the worldviews of two groups, Compassion & Choices and Not Dead Yet, are studied. The analysis concludes that the two organizations are more parallel than contrary--a finding that offers opportunities for dialogue and perhaps even advances in public policy. PMID:22204677

  19. Simulation of the CNE primary heat transport behaviour for a postulated boiler dividing plate change in case of a perturbation

    International Nuclear Information System (INIS)

    This work considers the increase of the inlet header temperatures as a reduction in the boiler heat transfer rate due to larger fouling coefficients and to damages in the divider plate between boiler inlet and outlet heads. A resistance is added to the heat transfer equation to get an inlet temperature of around 268 dec. C. We simulate the boiler dividing plate replacement by diminishing such resistance for all the boilers or for two of them. In addition, a perturbation which consists in the spurious opening and closing of the pressurizer pressure control valves PCV 5 and PCV 6, is analyzed. A two loop nodalization represents the CNE plant and the simulations are performed with the FIREBIRD code. The code results show that when only two divider plates are replaced the temperatures of the downstream inlet headers decrease. Nevertheless, the other two inlet header temperatures remain high. The effect of the perturbation vanishes with no effect on the stability of the system, regardless of the number of plates changed. Furthermore, small amplitude oscillations are observed throughout the calculations. The study of the nature of these oscillation is underway. (author)

  20. Metabolic Profiling of Dividing Cells in Live Rodent Brain by Proton Magnetic Resonance Spectroscopy (1HMRS) and LCModel Analysis

    DEFF Research Database (Denmark)

    Park, June-Hee; Lee, Hedok

    2014-01-01

    RATIONALE: Dividing cells can be detected in the live brain by positron emission tomography or optical imaging. Here we apply proton magnetic resonance spectroscopy (1HMRS) and a widely used spectral fitting algorithm to characterize the effect of increased neurogenesis after electroconvulsive shock in the live rodent brain via spectral signatures representing mobile lipids resonating at ?1.30 ppm. In addition, we also apply the same 1HMRS methodology to metabolically profile glioblastomas with actively dividing cells growing in RCAS-PDGF mice. METHODS: 1HMRS metabolic profiles were acquired on a 9.4T MRI instrument in combination with LCModel spectral analysis of: 1) rat brains before and after ECS or sham treatments and 2) RCAS-PDGF mice with glioblastomas and wild-type controls. Quantified 1HMRS data were compared to post-mortem histology. RESULTS: Dividing cells in the rat hippocampus increased ?3-fold after ECS compared to sham treatment. Quantification of hippocampal metabolites revealed significant decreases in N-acetyl-aspartate but no evidence of an elevated signal at ?1.3 ppm (Lip13a+Lip13b) in the ECS compared to the sham group. In RCAS-PDGF mice a high density (22%) of dividing cells characterized glioblastomas. Nile Red staining revealed a small fraction (3%) of dying cells with intracellular lipid droplets in the tumors of RCAS-PDGF mice. Concentrations of NAA were lower, whereas lactate and Lip13a+Lip13b were found to be significantly higher in glioblastomas of RCAS-PDGF mice, when compared to normal brain tissue in the control mice. CONCLUSIONS: Metabolic profiling using 1HMRS in combination with LCModel analysis did not reveal correlation between Lip13a+Lip13b spectral signatures and an increase in neurogenesis in adult rat hippocampus after ECS. However, increases in Lip13a+Lip13b were evident in glioblastomas suggesting that a higher density of actively dividing cells and/or the presence of lipid droplets is necessary for LCModel to reveal mobile lipids.