In: State politics & policy quarterly: the official journal of the State Politics and Policy section of the American Political Science Association, Band 7, Heft 3, S. 325-338
This article compares three approaches to handling missing data at the state level under three distinct conditions. Using Monte Carlo simulation experiments, I compare the results from a linear model using listwise deletion (LD), Markov Chain Monte Carlo with the Gibbs sampler algorithm (MCMC), and multiple imputation by chained equations (MICE) as approaches to dealing with different severity levels of missing data: missing completely at random (MCAR), missing at random (MAR), and nonignorable missingness (NI). I compare the results from each of these approaches under each condition for missing data to the results from the fully observed dataset. I conclude that the MICE algorithm performs best under most missing data conditions, MCMC provides the most stable parameter estimates across the missing data conditions (but often produced estimates that were moderately biased), and LD performs worst under most missing data conditions. I conclude with recommendations for handling missing data in state-level analysis.
In: State politics & policy quarterly: the official journal of the State Politics and Policy Section of the American Political Science Association, Band 7, Heft 3, S. 325-338
This article compares three approaches to handling missing data at the state level under three distinct conditions. Using Monte Carlo simulation experiments, I compare the results from a linear model using listwise deletion (LD), Markov Chain Monte Carlo with the Gibbs sampler algorithm (MCMC), and multiple imputation by chained equations (MICE) as approaches to dealing with different severity levels of missing data: missing completely at random (MCAR), missing at random (MAR), and nonignorable missingness (NI). I compare the results from each of these approaches under each condition for missing data to the results from the fully observed dataset. I conclude that the MICE algorithm performs best under most missing data conditions, MCMC provides the most stable parameter estimates across the missing data conditions (but often produced estimates that were moderately biased), and LD performs worst under most missing data conditions. I conclude with recommendations for handling missing data in state-level analysis. Adapted from the source document.
In: Political research quarterly: PRQ ; official journal of Western Political Science Association, Pacific Northwest Political Science Association, Southern California Political Science Association, Northern California Political Science Association, Band 52, Heft 4, S. 709-728
In: State politics & policy quarterly: the official journal of the State Politics and Policy Section of the American Political Science Association, Band 3, Heft 1, S. 84-89
The need to develop a system of collecting & circulating data concerning state politics is articulated. Although data regarding state politics have become more available during the late 20th century, it is argued that methods for collocating & disseminating such data remain inadequate. Three problems that have arisen from this failure to properly categorize state politics data are identified, eg, using informal networks for gathering information may reduce the empirical quality of state politics data. Consequently, it is announced that the journal State Politics & Policy Quarterly has initiated measures to periodically inform scholars about existing state politics data, especially from sources available via the Internet. Short synopses of the content of several Web sites that have state politics data readily available are also provided. 3 References. J. W. Parker
The race for superdelegate support during the extended competition between Hillary Clinton and Barack Obama for the 2008 Democratic presidential nomination offers a unique opportunity to examine the behavior of party elites with regard to their party's rank and file. The choice and timing of superdelegates' endorsements were examined, as well as measures of superdelegate loyalty, enthusiasm, considerations of candidate viability, and strategic endorsements. Did superdelegates endorse candidates based on personal or political ties, or to settle old political scores, as much of the press coverage suggested? Did superdelegates try to hijack the nomination for a candidate other than the one preferred by party rank‐and‐file participants in primaries and caucuses? We find that, taken in the aggregate, superdelegate endorsements were based on systematic considerations about candidates' standing as measured by national opinion polling, state support for candidates, and the candidate delegate count. Furthermore, female superdelegates showed more enthusiastic support for Clinton, while elected officials who were superdelegates were more likely to support Obama.Related Articles DeWitt, Jeff R. and Richard N. Engstrom. 2011. "." Politics & Policy 39 (): 741‐759. http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2011.00311.x/abstract
Bode, Leticia, and Valerie M. Hennings. 2012. "." Politics & Policy 40 (): 221‐257. http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2012.00350.x/abstract
Shafie, David M. 1998. ". Southeastern Political Review 26 (): 45‐77. http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.1998.tb00471.x/abstract Related Media Film Clips: 2008. "." . http://www.youtube.com/watch?v=CpzCBPE3j6k
. 2008 "Hillary Clinton Speech." http://www.c‐spanvideo.org/program/204090‐3 La carrera por el apoyo de los superdelegados durante la extensa competencia entre Hillary Clinton y Barack Obama por la nominación presidencial en 2008 del partido Demócrata ofrece una oportunidad única para examinar el comportamiento de la élite del partido en relación al resto de sus miembros. Se examinó la elección y coordinación de los superdelegados para expresar su apoyo, así como sus niveles de lealtad, entusiasmo, consideraciones de viabilidad del candidato, y ratificaciones estratégicas. ¿Fueron las ratificaciones de los superdelegados basadas en lazos políticos o personales? ¿Trataron los superdelegados de adueñarse de la nominación de un candidato que fuera diferente del preferido debido a su posición en el partido en las elecciones primarias y los cáucuses? Encontramos que en agregado, las ratificaciones de los superdelegados se basaron en consideraciones sistemáticas de la posición de los candidatos, medida por encuestas de opinión nacional, apoyo estatal por el candidato, y la cuenta de delegados del candidato. Además, las mujeres superdelegadas mostraron un apoyo más entusiasta por Clinton, mientras que oficiales elegidos que a su vez eran superdelegados mostraban una mayor probabilidad a apoyar a Obama.
The SoLid collaboration has developed a new detector technology to detect electron anti-neutrinos at close proximity to the Belgian BR2 reactor at surface level. A 288 kg prototype detector was deployed in 2015 and collected data during the operational period of the reactor and during reactor shut-down. Dedicated calibration campaigns were also performed with gamma and neutron sources. This paper describes the construction of the prototype detector with a high control on its proton content and the stability of its operation over a period of several months after deployment at the BR2 reactor site. All detector cells provide sufficient light yields to achieve a target energy resolution of better than 20%/root E(MeV). The capability of the detector to track muons is exploited to equalize the light response of a large number of channels to a precision of 3% and to demonstrate the stability of the energy scale over time. Particle identification based on pulse-shape discrimination is demonstrated with calibration sources. Despite a lower neutron detection efficiency due to triggering constraints, the main backgrounds at the reactor site were determined and taken into account in the shielding strategy for the main experiment. The results obtained with this prototype proved essential in the design optimization of the final detector. ; Agence Nationale de la Recherche, France [ANR-16 - CE31 - 0018 - 03]; Institut Carnot Mines, France; CNRS/IN2P3 et Region Pays de Loire, France; FWO-Vlaanderen, Belgium; Vlaamse Herculesstichting, Belgium; Science AMP; Technology Facilities Council (STFC), United Kingdom; Belgian Federal Science Policy Office (BelSpo) under the IUAP network programme; STFC Rutherford Fellowship program; European Research Council under the European Union's Horizon Programme (H-CoG)/ERC Grant [682474]; Merton College Oxford; FWO-Vlaanderen ; This work was supported by the following funding agencies: Agence Nationale de la Recherche grant ANR-16 - CE31 - 0018 - 03, Institut Carnot Mines, CNRS/IN2P3 et Region Pays de Loire, France; FWO-Vlaanderen and the Vlaamse Herculesstichting, Belgium; The U.K. groups acknowledge the support of the Science & Technology Facilities Council (STFC), United Kingdom; We are grateful for the early support given by the sub-department of Particle Physics at Oxford and High Energy Physics at Imperial College London. We thank also our colleagues, the administrative and technical staffs of the SCK . CEN for their invaluable support for this project. Individuals have received support from the FWO-Vlaanderen and the Belgian Federal Science Policy Office (BelSpo) under the IUAP network programme; The STFC Rutherford Fellowship program and the European Research Council under the European Union's Horizon 2020 Programme (H2020-CoG)/ERC Grant Agreement n. 682474 (corresponding author); Merton College Oxford.
The next generation of very-short-baseline reactor experiments will require compact detectors operating at surface level and close to a nuclear reactor. This paper presents a new detector concept based on a composite solid scintillator technology. The detector target uses cubes of polyvinyltoluene interleaved with (LiF)-Li-6:ZnS(Ag) phosphor screens to detect the products of the inverse beta decay reaction. A multi-tonne detector system built from these individual cells can provide precise localisation of scintillation signals, making efficient use of the detector volume. Monte Carlo simulations indicate that a neutron capture efficiency of over 70% is achievable with a sufficient number of 6LiF: ZnS( Ag) screens per cube and that an appropriate segmentation enables a measurement of the positron energy which is not limited by gamma-ray leakage. First measurements of a single cell indicate that a very good neutron-gamma discrimination and high neutron detection efficiency can be obtained with adequate triggering techniques. The light yield from positron signals has been measured, showing that an energy resolution of 14%/root E(MeV) is achievable with high uniformity. A preliminary neutrino signal analysis has been developed, using selection criteria for pulse shape, energy, time structure and energy spatial distribution and showing that an antineutrino efficiency of 40% can be achieved. It also shows that the fine segmentation of the detector can be used to significantly decrease both correlated and accidental backgrounds. ; Agence Nationale de la Recherche grant [ANR-16-CE31-0018-03]; Institut Carnot Mines, France; CNRS/IN2P3 et Region Pays de Loire, France; FWO-Vlaanderen, Belgium; Vlaamse Herculesstichting, Belgium; Science AMP; Technology Facilities Council (STFC), United Kingdom; FWO-Vlaanderen; Belgian Federal Science Policy Office (BelSpo) under the IUAP network programme; STFC Rutherford Fellowship program; European Research Council under the European Union's Horizon Programme (H-CoG) / ERC Grant [682474]; Merton College Oxford ; This work was supported by the following funding agencies: Agence Nationale de la Recherche grant ANR-16-CE31-0018-03, Institut Carnot Mines, CNRS/IN2P3 et Region Pays de Loire, France; FWO-Vlaanderen and the Vlaamse Herculesstichting, Belgium; The U.K. groups acknowledge the support of the Science & Technology Facilities Council (STFC), United Kingdom; We are grateful for the early support given by the sub-department of Particle Physics at Oxford and High Energy Physics at Imperial College London. We thank also our colleagues, the administrative and technical staffs of the SCK.CEN for their invaluable support for this project. Individuals have received support from the FWO-Vlaanderen and the Belgian Federal Science Policy Office (BelSpo) under the IUAP network programme; The STFC Rutherford Fellowship program and the European Research Council under the European Union's Horizon 2020 Programme (H2020-CoG) / ERC Grant Agreement n. 682474 (corresponding author); Merton College Oxford.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; FINEP (Brazil) ; NSFC (China) ; CNRS/IN2P3 (France) ; BMBF (Germany) ; DFG (Germany) ; HGF (Germany) ; SFI (Ireland) ; INFN (Italy) ; NASU (Ukraine) ; STFC (UK) ; NSF (USA) ; BMWFW (Austria) ; FWF (Austria) ; FNRS (Belgium) ; FWO (Belgium) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; MES (Bulgaria) ; CAS (China) ; MoST (China) ; COLCIENCIAS (Colombia) ; MSES (Croatia) ; CSF (Croatia) ; RPF (Cyprus) ; MoER (Estonia) ; ERC IUT (Estonia) ; ERDF (Estonia) ; Academy of Finland (Finland) ; MEC (Finland) ; HIP (Finland) ; CEA (France) ; GSRT (Greece) ; OTKA (Hungary) ; NIH (Hungary) ; DAE (India) ; DST (India) ; IPM (Iran) ; NRF (Republic of Korea) ; WCU (Republic of Korea) ; LAS (Lithuania) ; MOE (Malaysia) ; UM (Malaysia) ; CINVESTAV (Mexico) ; CONACYT (Mexico) ; SEP (Mexico) ; UASLP-FAI (Mexico) ; MBIE (New Zealand) ; PAEC (Pakistan) ; MSHE (Poland) ; NSC (Poland) ; FCT (Portugal) ; JINR (Dubna) ; MON (Russia) ; RosAtom (Russia) ; RAS (Russia) ; RFBR (Russia) ; MESTD (Serbia) ; SEIDI (Spain) ; CPAN (Spain) ; MST (Taipei) ; ThEPCenter (Thailand) ; IPST (Thailand) ; STAR (Thailand) ; NSTDA (Thailand) ; TUBITAK (Turkey) ; TAEK (Turkey) ; SFFR (Ukraine) ; DOE (USA) ; MPG (Germany) ; FOM (The Netherlands) ; NWO (The Netherlands) ; MNiSW (Poland) ; NCN (Poland) ; MEN/IFA (Romania) ; MinES (Russia) ; FANO (Russia) ; MinECo (Spain) ; SNSF (Switzerland) ; SER (Switzerland) ; Marie-Curie programme ; European Research Council ; EPLANET (European Union) ; Leventis Foundation ; A. P. Sloan Foundation ; Alexander von Humboldt Foundation ; Belgian Federal Science Policy Office ; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIABelgium) ; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium) ; Ministry of Education, Youth and Sports (MEYS) of the Czech Republic ; Council of Science and Industrial Research, India ; Foundation for Polish Science ; European Union, Regional Development Fund ; Compagnia di San Paolo (Torino) ; Consorzio per la Fisica (Trieste) ; MIUR (Italy) ; Thalis programme ; Aristeia programme ; EU-ESF ; Greek NSRF ; National Priorities Research Program by Qatar National Research Fund ; EPLANET ; Marie Sklodowska-Curie Actions ; ERC (European Union) ; Conseil general de Haute-Savoie ; Labex ENIGMASS ; OCEVU ; Region Auvergne (France) ; XuntaGal (Spain) ; GENCAT (Spain) ; Royal Society (UK) ; Royal Commission for the Exhibition of 1851 (UK) ; MIUR (Italy): 20108T4XTM ; The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. The probabilities, or branching fractions, of the strange B meson (B-s(0)) and the B-0 meson decaying into two oppositely charged muons (mu(+) and mu(-)) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B-s(0)->mu(+)mu(-) and B-0 ->mu(+)mu(-) decays are very rare, with about four of the former occurring for every billion B-s(0) mesons produced, and one of the latter occurring for every ten billion B-0 mesons(1). A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN2 started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid) and LHCb(Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton-proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the B-s(0)->mu(+)mu(-) decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. Furthermore, we obtained evidence for the B-0 ->mu(+)mu(-) decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton-proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B-s(0) and B-0 mesons and lead to further improvements in the precision of these crucial tests of the standard model.