The semileptonic B->pi decay in a Constituent Quark-Meson model

We evaluate the form factors describing the exclusive decay B-> pi l nu by using a Constituent Quark-Meson model based on an effective quark-meson Lagrangian (CQM). The model allows for an expansion in the pion momenta and we consider terms up to the first order in the pion field derivatives. We compute the leading terms in the soft pion limit and consider corrections to this limit.Comment: 6 pages, 3 figures, LaTeX (uses aps, epsf, revtex), formula 26 corrected, discussion enlarged, references updated and other minor change

Measurement of spin correlation in ttbar production using dilepton final states

We measure the correlation between the spin of the top quark and the spin of the anti-top quark in (ttbar -> W+ W- b bbar -> l+ nu b l- nubar bbar) final states produced in ppbar collisions at a center of mass energy sqrt(s)=1.96 TeV, where l is an electron or muon. The data correspond to an integrated luminosity of 5.4 fb-1 and were collected with the D0 detector at the Fermilab Tevatron collider. The correlation is extracted from the angles of the two leptons in the t and tbar rest frames, yielding a correlation strength C= 0.10^{+0.45}_{-0.45}, in agreement with the NLO QCD prediction within two standard deviations, but also in agreement with the no correlation hypothesis.Comment: 10 pages, 3 figures, submitted to PL

Exact Theorems Concerning CP and CPT Violations in C=-1 Entangled State of Pseudoscalar Neutral Mesons

Neutral pseudoscalar mesons in an entangled or Einstein-Podolsky-Rosen state are routinely produced in phi and B factories. Based on the peculiar properties of an entangled state, we present some general exact theorems about parameters characterizing CP and CPT violations, by using various asymmetries defined for the correlated decays of the two entangled mesons, which are rigorously calculated.Comment: 10 pages, published versio

The masses and decay widths of heavy hybrid mesons

We first derive the mass sum rules for the heavy hybrid mesons to obtain the binding energy and decay constants in the leading order of HQET. The pionic couplings between the lightest $1^{-+}$ hybrid $(Q\bar q g)$ and the lowest three heavy meson doublets are calculated with the light cone QCD sum rules. With $SU_f (3)$ flavor symmetry we calculate the widths for all the possible two-body decay processes with a Goldstone boson in the final state. The total width of the $1^{-+}$ hybrid is estimated to be 300 MeV. We find the dominant decay mode of the $1^{-+}$ hybrid is $1^{-+}\to \pi + 1^+$ where the $1^+$ heavy meson belongs to the $(1^+,2^+)$ doublet. Its branching ratio is about 80% so this mode can be used for the experimental search of the lowest heavy hybrid meson.Comment: 20 pages + 12 PS figures, introduction revised, Fig 7 updated, to appear in Phys. Rev.

A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

El Pensamiento Probabilístico de los Profesores de Biología en Formación

Los futuros profesores de secundaria requieren de una formación acorde a las demandas de la sociedad del siglo XXI. Ello impone el desarrollo de un pensamiento que le permita interpretar y abordar los fenómenos de naturaleza aleatoria. El objetivo de este trabajo es determinar las tendencias de pensamiento probabilístico de los estudiantes de los profesorados de Biología de la provincia de Mendoza, Argentina. Para ello se aplicó un cuestionario a los 325 estudiantes que cursan esta carrera. El mismo consta de tres partes; la primera trata sobre las variables demográficas de los estudiantes, la segunda corresponde al reconocimiento de la aleatoriedad; y la tercera a la estimación de la probabilidad de diferentes sucesos. Las respuestas se analizaron a partir de la aplicación de diferentes técnicas estadísticas; el test de independencia, el análisis de la varianza, el test de Tukey, análisis de clusters y análisis discriminante. En primer lugar, se encontraron diferencias significativas entre el reconocimiento de la aleatoriedad y el contexto del suceso, siendo mayor en el contexto de juego que en el físico natural. Mientras que, en el contexto físico natural se afirma la aleatoriedad desde la causalidad, en el de juego se afirma desde la incertidumbre. En segundo lugar, no se encontró relación de dependencia entre el reconocimiento de la aleatoriedad y la edad de los estudiantes, como así tampoco con el nivel académico de los mismos. Respecto a la estimación de la probabilidad, los estudiantes argumentan fundamentalmente desde la equiprobabilidad y desde la contingencia. El análisis de clusters y análisis discriminante permitieron encontrar cuatro tendencias de pensamiento: incertidumbre, determinista, contingente y personalista

State of nature

For the first time ever, the UK’s wildlife organisations have joined forces to undertake a health check of nature in the UK and its Overseas Territories. 60% of the 3,148 UK species we assessed have declined over the last 50 years and 31% have declined strongly. Half of the species assessed have shown strong changes in their numbers or range, indicating that recent environmental changes are having a dramatic impact on nature in the UK. Species with specific habitat requirements seem to be faring worse than generalist species. A new Watchlist Indicator, developed to measure how conservation priority species are faring, shows that their overall numbers have declined by 77% in the last 40 years, with little sign of recovery. Of more than 6,000 species that have been assessed using modern Red List criteria, more than one in 10 are thought to be under threat of extinction in the UK. Our assessment looks back over 50 years at most, yet there were large declines in the UK’s wildlife prior to this, linked to habitat loss. The UK’s Overseas Territories hold a wealth of wildlife of huge international importance and over 90 of these species are at high risk of global extinction. There is a lack of knowledge on the trends of most of the UK’s species. As a result, we can report quantitative trends for only 5% of the 59,000 or so terrestrial and freshwater species in the UK, and for very few of the 8,500 marine species. Much needs to be done to improve our knowledge. What we do know about the state of the UK’s nature is often based upon the efforts of thousands of dedicated volunteer enthusiasts who contribute their time and expertise to monitoring schemes and species recording. The threats to the UK’s wildlife are many and varied, the most severe acting either to destroy valuable habitat or degrade the quality and value of what remains. Climate change is having an increasing impact on nature in the UK. Rising average temperatures are known to be driving range expansion in some species, but evidence for harmful impacts is also mounting. The full report is online: www.rspb.org.uk/stateofnature We should act to save nature both for its intrinsic value and for the benefits it brings to us that are essential to our wellbeing and prosperity. Targeted conservation has produced inspiring success stories and, with sufficient determination, resources and public support, we can turn the fortunes of our wildlife around. The State of Nature report serves to illustrate that with shared resolve and commitment we can save nature

Advancement of flash hydrogasification: Task VIII. Performance testing

This topical report documents the technical effort required to investigate and verify the reaction chemistry associated with the Rockwell Advanced Flash Hydropyrolysis (AFHP) concept for the production of substitute natural gas (SNG) from coal. The testing phase of the program included 5 preburner performance evaluation tests (14 test conditions) and 11 coal-fed reactor tests (19 test conditions). The reactor test parameters investigated spanned exist temperatures from 1775 to 2050/sup 0/F, residence times from 2 to 8 s, inlet gas-to-coal ratios from 0.15 to 0.27 lb-mole/lb, and inlet-steam-to-H/sub 2/ mole ratios from 0.15 to 0.86. One test was conducted to investigate the effect of CH/sub 4/ addition to the hydrogen feed stream (22 mole % CH/sub 4/), with subsequent partial oxidation of the CH/sub 4/ to CO/sub x/ in the preburner system, on the AFHP reactor chemistry and product gas composition. Overall carbon conversion and total carbon conversion to gases (namely, CH/sub 4/, C/sub 2/H/sub 6/, CO, and CO/sub 2/) ranged from 53 to 68% and 35 to 68%, respectively. The gas produced was primarily CH/sub 4/ (31 to 53% carbon conversion to CH/sub 4/). Carbon conversion to total liquids was strongly dependent on reactor exit temperature and to a lesser extent on residence time, with values ranging from about 20% to 1775/sup 0/F and 2-S residence time to zero at 1975/sup 0/F and residence times greater than 5 s. Carbon conversion to C/sub 6/H/sub 6/ asd high as 11.2% was obtained. Carbon conversion to CO/sub x/ ranged from 3.5 to 29.4%. Methane addition was found not to significantly affect the AFHP reactor chemistry. As a result of this program, Rockwell has expanded its data base and significantly improved its correlation model describing the processes occurring during flash hydropyrolysis. The correlation provides an excellent tool for subsequent process evaluations to determine the economic potential of the Rockwell coal hydrogasification process. 23 refs., 51 figs., 31 tabs