Polarization

Distribution by Scientific Domains
Distribution within Physics and Astronomy

Kinds of Polarization

  • b-mode polarization
  • cell polarization
  • circular polarization
  • cross polarization
  • dynamic nuclear polarization
  • fluorescence polarization
  • in-plane polarization
  • light polarization
  • linear polarization
  • membrane polarization
  • neuronal polarization
  • nuclear polarization
  • nuclear spin polarization
  • optical polarization
  • remanent polarization
  • remnant polarization
  • solvent polarization
  • spin polarization
  • spontaneous polarization
  • th1 polarization
  • th17 polarization
  • th2 polarization

  • Terms modified by Polarization

  • polarization anisotropy
  • polarization characteristic
  • polarization component
  • polarization curve
  • polarization data
  • polarization degree
  • polarization dependence
  • polarization direction
  • polarization effect
  • polarization effects
  • polarization energy
  • polarization field
  • polarization function
  • polarization immunoassay
  • polarization measurement
  • polarization model
  • polarization observation
  • polarization property
  • polarization resistance
  • polarization state
  • polarization states
  • polarization survey
  • polarization switching
  • polarization technique
  • polarization transfer
  • polarization vector

  • Selected Abstracts


    Caveolin-1 polarization in migrating endothelial cells is directed by substrate topology not chemoattractant gradient

    CYTOSKELETON, Issue 11 2006
    Virginie Santilman
    Abstract Polarization is a hallmark of migrating cells, and an asymmetric distribution of proteins is essential to the migration process. Caveolin-1 is highly polarized in migrating endothelial cells (EC). Several studies have shown caveolin-1 accumulation in the front of migrating EC while others report its accumulation in the EC rear. In this paper we address these conflicting results on polarized localization of caveolin-1. We find evidence for the hypothesis that different modes of locomotion lead to differences in protein polarization. In particular, we show that caveolin-1 is primarily localized in the rear of cells migrating on a planar substrate, but in the front of cells traversing a three-dimensional pore. We also show that a chemoattractant, present either as a gradient or ubiquitously in the medium, does not alter caveolin-1 localization in cells in either mode of locomotion. Thus we conclude that substrate topology, and not the presence of a chemoattractant, directs the polarization of caveolin-1 in motile ECs. Cell Motil. Cytoskeleton 2006. 2006 Wiley-Liss, Inc. [source]


    Galvanostatic Polarization of All-Solid-State K+ -Selective Electrodes with Polypyrrole Ion-to-Electron Transducer

    ELECTROANALYSIS, Issue 13-14 2006
    owski
    Abstract Influence of galvanostatic polarizations on potential vs. logarithm of ion activity dependences of all-solid-state ion-selective electrodes with conducting polymer ion-to-electron transducer was studied. As a model system K+ -sensor with polypyrrole solid contact and poly(vinyl chloride) based membrane containing valinomycin was chosen. The influence of the lipophilic salt included to the membrane composition was of special interest. [source]


    Robustness of Spin Polarization in Graphene-Based Spin Valves

    ADVANCED FUNCTIONAL MATERIALS, Issue 23 2009
    Masashi Shiraishi
    Abstract The decrease of spin polarization in spintronics devices under the application of a bias voltage is one of a number of currently important problems that should be solved. Here, an unprecedented robustness of the spin polarization in multilayer-graphene spin valves at room temperature is revealed. Surprisingly, the spin polarization of injected spins is constant up to a bias voltage of +2.7,V and ,0.6,V in positive- and negative-bias voltage applications at room temperature, respectively, which is superior to all spintronics devices. This finding is induced by suppression of spin scattering due to an ideal-interface formation. Furthermore, an important accordance between theory and experiment in molecular spintronics is found by observing the fact that the signal intensity in a local scheme is double that in a nonlocal scheme, as theory predicts, which provides construction of a steadfast physical basis in this field. [source]


    Social Polarization and the Politics of Low Income Mortgage Lending in the United States

    GEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 3 2003
    Jason Hackworth
    ABSTRACT The structured inequalities of capital investment and disinvestment are prominent themes in critical urban and regional research, but many accounts portray ,capital' as a global, faceless and placeless abstraction operating according to a hidden, unitary logic. Sweeping political-economic shifts in the last generation demonstrate that capital may shape urban and regional processes in many different ways, and each of these manifestations creates distinct constraints and opportunities. In this paper, we analyze a new institutional configuration in the USA that is reshaping access to wealth among the poor , a policy ,consensus' to expand home-ownership among long-excluded populations. This shift has opened access to some low- and moderate-income households, and racial and ethnic minorities, but the necessary corollary is a greater polarization between those who are able to own and those who are not. We provide a critical analysis of these changes, drawing on national housing finance statistics as well as a multivariate analysis of differences between owners and renters in the 1990s in New York City. As home-ownership strengthens its role as a privatized form of stealth urban and housing policy in the USA, its continued expansion drives a corresponding reconstruction of its value for different groups, and inscribes a sharper axis of property-rights inequalities among owners and renters in the working classes. [source]


    Ethnicity, Economic Polarization and Regional Inequality in Southern Slovakia

    GROWTH AND CHANGE, Issue 2 2000
    Adrian Smith
    This paper examines the relationships between ethnicity and regional economic transformation in Slovakia. It takes as its focus the position of the Hungarian minority in Slovakia in the uneven process of regional change. The paper places these issues within the context of struggles over ethnicity and ,nation' in post-independence Slovakia. The paper argues that ethnicity has been a thoroughly contested issue since the collapse of ,communism' in Slovakia and a variety of struggles have been waged over enhancing the rights and position of the Hungarian minority population. The concentration of the Hungarian minority in the southern Slovak border regions with Hungary is examined within the context of the uneven economic impacts of the ,transition to capitalism'. It is argued that, while the economic decline seen in many of these ,Hungarian' regions has impacted negatively on the local populations, the roots of these changes lie within the ways in which such regions were integrated into the state socialist regional division of labor. In particular, the role of peripheral industrialization in such regions prior to 1989, in attempting to reduce economic differences among various ethnic groups, resulted in the establishment of branch plant economies which have had difficulty in surviving since 1989. It is therefore the interweaving of the economics of regional decline and the politics of ethnicity that help us to understand the complex place of the Hungarian minority in Slovakia. [source]


    Nuclear-Spin Polarization in Electron-Transfer Reactions of Amines

    HELVETICA CHIMICA ACTA, Issue 12 2006
    Heinz
    Abstract Chemically induced dynamic nuclear polarization (CIDNP) observed during electron transfer (ET) reactions of tertiary amines such as DABCO (1) or Et3N (2) with a wide range of electron acceptors support the involvement of amine radical-cations (e.g., 1.+ or 2.+) as key intermediates. Radical ions such as 2.+ may be deprotonated, generating neutral aminoalkyl radicals (e.g., 2.). When generated by reaction with an electron acceptor of energetically low triplet state such as naphthalene (1Naph*), the resulting pair 2.+/Naph., reacts mostly by reverse electron transfer (RET) from triplet pairs populating the naphthalene triplet state. [source]


    The Discovery of Chemically Induced Dynamic Polarization (CIDNP)

    HELVETICA CHIMICA ACTA, Issue 10 2006
    Joachim Bargon
    First page of article [source]


    Polymer Photovoltaic Cells Sensitive to the Circular Polarization of Light

    ADVANCED MATERIALS, Issue 20 2010
    Jan Gilot
    Chiral conjugated polymer is used to construct a photovoltaic cell whose response depends on the circular polarization of the incoming light. The selectivity for left and right polarized light as a function of the thickness of the polymer layer is accounted for by modeling of the optical properties of all layers inside the device. [source]


    Large Electric Polarization and Exchange Bias in Multiferroic BiFeO3,

    ADVANCED MATERIALS, Issue 11 2006
    J. Dho
    Low-leakage BiFeO3 films have been grown with saturated ferroelectric hysteresis loops (see figure) and a very large remanent polarization. The antiferromagnetic nature of BiFeO3 films is confirmed by the appearance of an exchange bias in BiFeO3 -based spin-valve multilayers. The results imply that there is potential for room-temperature applications of BiFeO3 that combine ferroelectric and antiferromagnetic functionality. [source]


    Polarization switching in BaTiO3 thin films measured by X-ray diffraction exploiting anomalous dispersion

    JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2004
    S. J. Van Reeuwijk
    Films of BaTiO3 ranging from 20,nm to 300,nm in thickness were grown with pulsed laser deposition on Nb:SrTiO3. The quality of the layers was investigated using atomic force microscopy, X-ray reflectivity and X-ray diffraction. Both the micrographs and the X-ray reflectivity spectra indicate a smooth surface of the layers. The X-ray diffraction profiles measured using synchrotron radiation show features characteristic for highly crystalline thin films. The application of an external electric field parallel to the c axis changes an hkl reflection of BaTiO3 to an hk reflection. Due to the anomalous dispersion, the intensities of these two reflections are not equal and the atomic displacements can be determined from the intensity differences. The electric field-induced intensity changes can be as large as a few percent, which makes data collection from a 100,nm film using Cu K, radiation from an X-ray tube feasible. The ,I/I values of a number of reflections from the 20 and 50,nm films were measured using synchrotron radiation. The observed ,I/I values were in good agreement with the intensity changes expected for polarization switching in the bulk. [source]


    Making inferences about the polarization, welfare and poverty of nations: a study of 101 countries 1970,1995

    JOURNAL OF APPLIED ECONOMETRICS, Issue 5 2004
    Gordon Anderson
    Stochastic Dominance techniques are adapted and employed to study the extent and progress of Polarization, Welfare and Poverty of 101 nations over the period 1970,1995. The adaptations provide methods of comparing mass relocation by evaluating various degrees of right and left separation between distributions. The results reveal that, whilst welfare increased and then diminished and poverty diminished and then increased, polarization between rich and poor countries continued unabated throughout the period emphasizing the distinction between polarization and inequality. Copyright 2004 John Wiley & Sons, Ltd. [source]


    Virtual Electrode Polarization Leads to Reentry in the Far Field

    JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2001
    ANNETTE E. LINDBLOM M.S.
    Virtual Electrode Polarization. Introduction: Our previous article examined cardiac vulnerability to reentry in the near field within the framework of the virtual electrode polarization (VEP) concept. The present study extends this examination to the far field and compares its predictions to the critical point hypothesis. Methods and Results: We simulate the electrical behavior of a sheet of myocardium using a two-dimensional bidomain model. The fiber field is extrapolated from a set of rabbit heart fiber directions obtained experimentally. An S1 stimulus is applied along the top or left border. An extracellular line electrode on the top delivers a cathodal or anodal S2 stimulus. A VEP pattern matching that seen experimentally is observed and covers the entire sheet, thus constituting a far-field effect. Reentry arises from break excitation, make excitation, or a combination of both, and subsequent propagation through deexcited and recovered areas. Reentry occurs in cross-field, parallel-field, and uniform refractoriness protocols. For long coupling intervals (CIs) above CImakemin (defined as the shortest CI at which make excitation can take place), rotors move away from the cathodal electrode and the S1 site for increases in S2 strength and CI, respectively. For cathodal S2 stimuli, findings are consistent with the critical point hypothesis. For CIs below CImakemin, reentry is initiated by break excitation only, and the resulting reentrant patterns are no longer consistent with those predicted by the critical point hypothesis. Conclusion: Shock-induced VEP can explain vulnerability in the far field. The VEP theory of vulnerability encompasses the critical point hypothesis for cathodal S2 shocks at long CIs. [source]


    Microbial Reduction Efficiencies of Filtration, Electrostatic Polarization, and UV Components of a Germicidal Air Cleaning System

    JOURNAL OF FOOD SCIENCE, Issue 6 2002
    C.J. Cundith
    ABSTRACT: This study determined the effectiveness of components of a germicidal air-cleaning system involving filtration, electrostatic polarization, and UV light on the reduction of airborne bacteria and molds. The filter alone, filter and electrostatic polarization combined, and the filter, electrostatic polarization, and UV light were found to be effective (P < 0.05) in reducing a given concentration of M. luteus and S. marcescens by 90 to 92%. The same components were also found to be effective (P < 0.05) in reducing indigenous airborne bacteria and molds from ambient air in processing plant production conditions by 62 to 77% after only 1 pass through the filtration system. A germicidal air-filtration system utilizing electrostatic polarization and ultraviolet light can be used to reduce the chance of contaminating surfaces with airborne bacteria and molds. [source]


    Fluorene-based liquid crystalline networks with linearly polarized blue emission

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2007
    Marta Millaruelo
    Abstract A series of fluorene-based luminophores containing methacrylic end groups have been prepared and incorporated into uniaxially oriented liquid crystalline films by in situ photopolymerization. Various structural modifications on the 2-(4-cyanophenyl)fluorene core, which include alkyl chains at the 9-position and elongation of the rigid core with one additional phenyl ring, have been investigated to generate emitters with adjusted liquid crystal compatibility, improved luminescence and dichroic properties. Polarized blue-emitting films were produced that had an acceptable photostability, and it was found that the polarization emission was better for samples with low (5%) cross-linker contents. Polarization of the luminescence was favored by the liquid crystalline properties of the luminophore. In addition, the detrimental effect of the alkyl substituent at the fluorene core on the mesomorphism and on the emission polarization can be overcome by lengthening the ,-system. 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4804,4817, 2007 [source]


    Bilayered BiFe0.95Mn0.05O3/Bi0.90La0.10FeO3 Thin Films with Low Ferroelectric Coercivity and Large Remanent Polarization

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2010
    Jiagang Wu
    Bilayered thin films consisting of (Bi0.90La0.10)FeO3 and Bi(Fe0.95Mn0.05)O3, i.e., Bi(Fe0.95Mn0.05)O3/(Bi0.90La0.10)FeO3, were deposited on SrRuO3 buffered SrTiO3(111) substrates by off-axis radio frequency magnetic sputtering, where (111)-oriented bilayered thin films were obtained. The bilayered Bi(Fe0.95Mn0.05)O3/(Bi0.90La0.10)FeO3 thin film possesses a lower coercive field (2Ec,335.6 kV/cm) and a larger remanent polarization (2Pr,155.2 ,C/cm2) at room temperature, and a higher relative permittivity as compared with those of single-layer (Bi0.90La0.10)FeO3 and Bi(Fe0.95Mn0.05)O3 thin films, together with an improvement of the magnetic properties (2Ms,31.2 emu/cm3). The bottom (Bi0.90La0.10)FeO3 nanolayer promotes the growth of the Bi(Fe0.95Mn0.05)O3 layer, which are largely responsible for the multiferroic behavior observed. [source]


    Temperature-Insensitive Large Strain of (Bi1/2Na1/2)TiO3,(Bi1/2K1/2)TiO3,(K0.5Na0.5)NbO3 Lead-Free Piezoceramics

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2010
    Klaus T. P. Seifert
    The effect of (K0.5Na0.5)NbO3 (KNN) addition on the ferroelectric behavior of (Bi1/2Na1/2)TiO3,(Bi1/2K1/2)TiO3 (BNT,BKT) lead-free piezoceramics was investigated. Polarization and strain hysteresis loops indicate that the ferroelectric order is disrupted significantly with the addition of KNN as a replacement for BNT and the destabilization of the ferroelectric order is accompanied by an enhancement of the unipolar strain, which peaks at a value of ,0.48% (corresponding to a large signal d33 of ,600 pm/V) at 1 mol% KNN content. This strain was analyzed as derived from an electrostrictive effect at lower electric fields and a converse piezoelectric effect at higher electric fields. By limiting the electric driving field to exclude the contribution from the converse piezoelectric effect, a temperature-insensitive large-field d33 of ,250 pm/V up to 200C was achieved. [source]


    Inspection of Remanent Polarization in the Ferroelectric Ceramic PZT 95/5 Through Pyroelectric Effect

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2007
    Fu-Ping Zhang
    Shock-induced depoling of the ferroelectric (FE) ceramic PZT 95/5 is utilized in a number of pulsed power devices. Nondestructive testing of remanent polarization of PZT 95/5 is developed by pyroelectric effect in this paper. Approximately linear relation between the change of polarization during low- to high-temperature rhombohedral FE phase and the remanent polarization was found through pyroelectricity of a single piece of PZT 95/5 ceramics. The change of polarization of a prototype for shock-driven pulsed power during the FEHT,FELT phase transformation was also investigated through directly measuring the pyroelectric current. Results indicate that pyroelectric effect caused by the reversible FEHT,FELT phase transition could be used as a non-destructive inspection for the remanent polarization of a prototype about shock-driven pulsed power supply. [source]


    Chemokine Receptor 2 (CCR2) in Atherosclerosis, Infectious Diseases, and Regulation of T-Cell Polarization

    MICROCIRCULATION, Issue 3-4 2003
    ISRAEL F. CHARO
    ABSTRACT Infiltration of tissues by monocyte-derived macrophages is a prominent component of a wide-range of diseases, including atherosclerosis, glomerulonephritis, encephalitis, infectious diseases, and virtually all syndromes characterized by chronic inflammation. The molecular signals responsible for this directed migration are incompletely understood, but members of the chemokine family, especially the monocyte chemoattractant proteins (MCPs) (MCP-1 to MCP-5) are emerging as key players. Cells that respond to the MCPs do so because they express chemokine receptor 2 (CCR2), the cognate receptor. This review will summarize evidence supporting a key role for CCR2 in the pathogenesis of atherosclerosis, infections with intracellular pathogens, and regulation of the type I adaptive immune response. [source]


    Intraoperative Study of Polarization and Evoked Response Signals in Different Endocardial Electrode Designs

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2001
    CHING LAU
    LAU, C., et al.: Intraoperative Study of Polarization and Evoked Response Signals in Different Endocardial Electrode Designs. Some new generation pacemakers use an algorithm based on evoked response (ER) detection to verify beat-to-beat capture and to enable automatic adjustment of output. This is a prospective acute study of polarization signal (PS) and ER in nine currently available electrodes. Intraoperative testing of ventricular bipolar electrodes used the Autocapture (AC) algorithm. The intrinsic R wave, PS, ER, acceptance of AC function, and stimulation thresholds (STs) were obtained. Ventricular electrodes were categorized as follows: titanium nitride (TiN)-coated passive and active fixation, high impedance (HI), passive fixation (VP), iridium oxide-coated titanium (IROX) (VI), and platinum helix (PH) active fixation. Acute testing was performed in 217 patients with an average age of 74.26 years, 59.6% were men with primary pacing indication-SSS (46.3%). There were no significant differences found with respect to R wave and threshold between the various electrodes. PH active-fixation electrodes had significantly higher ER and PS than other groups including the TiN-coated active-fixation electrodes. TiNcoated electrodes (active and passive fixation) had significantly lower PS than other electrodes. As a result, TiN electrodes had a significantly higher functional rate of AC (91.7%), whereas PH had the lowest rate (0%). In conclusion, (1) polarization characteristics are significantly different for commercially available ventricular electrodes, (2) certain physical features at the tissue to electrode interface like TiN coating appears to be more important in determining PS than electrode tip size and fixation method, and (3) the current algorithm for AC requires electrodes that provide low polarization for satisfactory performance. [source]


    Improved Differentiation of the Ventricular Evoked Response from Polarization by Modification of the Pacemaker Impulse

    PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2000
    FRANK PROVENIER
    The Autocapture feature, implemented in the Microny and Regency pacemakers of St. Jude Medical, continuously controls the effectiveness of ventricular stimulation by detection of the evoked response. Proper sensing of this signal depends on the magnitude of the polarization, which should be minimal. Therefore, the conjunctive use of low polarization electrodes is recommended. Further, the pacing impulse of these pacemakers has a biphasic waveform consisting of a stimulus followed by a fast discharge pulse. This study compares polarization of a modified pacing impulse with the default pacing impulse, and its effect on the ability to activate the Autocapture function when used with different types of electrodes. In 45 patients, acute measurements of the polarization and the evoked response were performed at random on the modified pacing impulses of a custom designed Regency and on the default stimuli of a standard Regency. The following bipolar leads were used: 20 Medtronic 4024 CapSure, 12 Pacesetter 1450T. and 13 Pacesetter 14701. Using the default pacing impulse, polarization and evoked response were significantly larger with the Medtronic 4024 CapSure compared to the low polarization leads. The polarization to evoked response ratio was more frequently acceptable for activation of the Autocapture with the Pacesetter leads. In all leads the modified pacing impulse was characterized bv significantly smaller polarization with the most prominent reduction in the Medtronic 4024 CapSure. The differences in the pacing impulse did not affect the evoked response. With the programmability of the fast discharge pulse, the requirements to activate the Autocapture function were fulfilled in 29 (94%) of 31 patients with the modified pacing impulse, compared to 22 (71%) of 31 patients with the standard pacing impulse. The modified pacing impulse decreased the "polarization to evoked response" ratio, and by that improved the conditions for activation of the Autocapture function. [source]


    Polarization of eigenmodes in laser diode waveguides on semipolar and nonpolar GaN

    PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 1-2 2010
    Jens Rass
    Abstract Recent calculations of the eigenmodes in waveguides grown on semipolar GaN suggest that the optical polarization of the emitted light as well as the optical gain depends on the orientation of the resonator. Our measurements on separate confinement heterostructures on semipolar (112) and (102) GaN show that for laser resonators along the semipolar [11] and [011] directions (i.e. the projection of the c -axis onto the plane of growth) the threshold for amplified spontaneous emission is lower than for the nonpolar direction and that the stimulated emission is linearly polarized as TE mode. For the waveguide structures along the nonpolar [100] or [110] direction on the other hand, birefringence and anisotropy of the optical gain in the plane of growth leads not only to a higher threshold but alsoto a rotation of the optical polarization which is not any more TE- or TM-polarized but influenced by the ordinary and extraordinary refractive index of the material. We observe stimulated emission into a mode which is linearly polarized in extraordinarydirection nearly parallel to the c -axis. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Polarization of electron spin in two barrier system based on semimagnetic semiconductors

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2006
    S. B. Lev
    Abstract The spin-dependent tunneling of electrons through a two barrier semiconductor heterostructure with a semimagnetic layer was investigated. It was shown that the resonant level splitting in the semimagnetic well under an external magnetic field allows achieving a high level of spin polarization of the current flowing through the proposed spin filter. The dependence of the polarization depth on the parameters of the sample was calculated in the two component diffusion transport model. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Polarization controlled edge emission from columnar InAs/GaAs self-assembled quantum dots

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2003
    T. Kita
    Abstract Polarization anisotropy of photoluminescence (PL) from the cleaved edge surface of columnar InAs/GaAs self-assembled quantum dots (QDs) has been investigated. The columnar QDs were fabricated by closely stacking the Stranski-Krastanov-mode InAs-island layers. PL peak energy and anisotropy of the PL polarization sensitively depends on the stacking layer number. Whereas the single-island-layer sample shows strong transverse-electric (TE)-mode PL, the PL-intensity ratio of TE-mode PL to transverse-magnetic (TM)-mode PL decreases with increasing stacking layer number. The polarization inversion of TE/TM-mode PL-intensity ratio has been accomplished beyond the stacking layer number of 9. The polarization spectra of the columnar QDs with >9 stacking layers indicate that TM-mode becomes dominant near the ground state transition. [source]


    The Political Economy of Polarization: The Italian Case, 1963,1987

    POLITICS & POLICY, Issue 1 2003
    Riccardo Pelizzo
    Economic voting in Italy has received scant attention in the literature, and the few studies available show little or no empirical support for economic voting hypotheses as applied to Italy. We argue that this dearth of results is primarily due to poor operationalization and study design. In contrast to previous studies that focused on the relationship between the state of the economy and the electoral performance of individual parties, we investigate the impact of prices, employment, and economic output on the polarization of the party system. Using data on seven Italian national elections covering the period 1963,87, we show that polarization is, in fact, closely related to macroeconomic performance. Additionally, in contrast to past studies of Italy, the results are robust with respect to the lag period of the economic variables. [source]


    Polls and Elections: Opinion Formation, Polarization, and Presidential Reelection

    PRESIDENTIAL STUDIES QUARTERLY, Issue 3 2009
    BARRY C. BURDEN
    The authors examine the dynamics of public opinion formation and change around a sitting president and their implications for reelection contests. Because of the biases inherent in information processing and the information environment, two distinct, but simultaneous, effects of citizen learning during a presidential term are expected. For those with prior opinions of the president, learning contributes to more polarized evaluations of the president. For those initially uncertain about the president, learning contributes to opinion formation about the president. Because the gap in uncertainty generally favors the incumbent over a lesser-known challenger, races with an incumbent presidential candidate are typically marked, perhaps paradoxically, by both a polarization of public opinion and an incumbency advantage. [source]


    Partisan Polarization and Congressional Accountability in House Elections

    AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 2 2010
    David R. Jones
    Early research led scholars to believe that institutional accountability in Congress is lacking because public evaluations of its collective performance do not affect the reelection of its members. However, a changed partisan environment along with new empirical evidence raises unanswered questions about the effect of congressional performance on incumbents' electoral outcomes over time. Analysis of House reelection races across the last several decades produces important findings: (1) low congressional approval ratings generally reduce the electoral margins of majority party incumbents and increase margins for minority party incumbents; (2) partisan polarization in the House increases the magnitude of this partisan differential, mainly through increased electoral accountability among majority party incumbents; (3) these electoral effects of congressional performance ratings hold largely irrespective of a member's individual party loyalty or seat safety. These findings carry significant implications for partisan theories of legislative organization and help explain salient features of recent Congresses. [source]


    Does Gerrymandering Cause Polarization?

    AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 3 2009
    Nolan McCarty
    Both pundits and scholars have blamed increasing levels of partisan conflict and polarization in Congress on the effects of partisan gerrymandering. We assess whether there is a strong causal relationship between congressional districting and polarization. We find very little evidence for such a link. First, we show that congressional polarization is primarily a function of the differences in how Democrats and Republicans represent the same districts rather than a function of which districts each party represents or the distribution of constituency preferences. Second, we conduct simulations to gauge the level of polarization under various "neutral" districting procedures. We find that the actual levels of polarization are not much higher than those produced by the simulations. We do find that gerrymandering has increased the Republican seat share in the House; however, this increase is not an important source of polarization. [source]


    Race and the Recall: Racial and Ethnic Polarization in the California Recall Election

    AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 2 2008
    Gary M. Segura
    In the 2003 recall election in California, Lt. Gov. Cruz Bustamante received more than 1.25 million fewer votes in the replacement election than votes cast against the recall of Gray Davis. A much smaller group voted "yes" on the recall but voted for Bustamante. The principal underlying explanation is racial and ethnic polarization. Using L.A. Times exit poll data, we compare the characteristics of voters who displayed the two unusual behavioral patterns with those who voted in more conventional ways. We find that Latinos and African Americans are far less likely than non-Hispanic whites and Asian Americans to have defected from Bustamante given a "no" vote on the recall, and far more likely to have voted for Bustamante given a potentially strategic "yes" vote on the recall. The patterns of defection are consistent with racial polarization on Proposition 54, lending further credence to our claim that race and ethnicity persists as an important factor in vote choice, even in environments with a history of minority electoral success. [source]


    Transparency, Political Polarization, and Political Budget Cycles in OECD Countries

    AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 3 2006
    James E. Alt
    We investigate the effects of fiscal transparency and political polarization on the prevalence of electoral cycles in fiscal balance. While some recent political economy literature on electoral cycles identifies such cycles mainly in weak and recent democracies, in contrast we show, conditioning on a new index of institutional fiscal transparency, that electoral cycles in fiscal balance are a feature of many advanced industrialized economies. Using a sample of 19 OECD countries in the 1990s, we identify a persistent pattern of electoral cycles in low(er) transparency countries, while no such cycles can be observed in high(er) transparency countries. Furthermore, we find, in accordance with recent theory, that electoral cycles are larger in politically more polarized countries. [source]


    The Law of Group Polarization

    THE JOURNAL OF POLITICAL PHILOSOPHY, Issue 2 2002
    Cass R. Sunstein
    First page of article [source]