10,158 research outputs found
First observation of Bs0 â D*s2+XÎŒ-Îœ decays
Using data collected with the LHCb detector in protonâproton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays B0sâD+sXÎŒâÎœ and B0sâD0K+XÎŒâÎœ are detected. Two structures are observed in the D0K+ mass spectrum at masses consistent with the known Ds1(2536)+ and Dâs22573)+ mesons. The measured branching fractions relative to the total B0s semileptonic rate are B(B0sâDâ+s2XÎŒâÎœ)/B(B0sâXÎŒâÎœ) = (3.3±1.0±0.4)%, and B(B0sâD+s1XÎŒâÎœ)/B(B0sâXÎŒâÎœ) = (5.4±1.2±0.5)%, where the ïŹrst uncertainty is statistical and the second is systematic. This is the ïŹrst observation of the Dâ+s2 state in B0s decays; we also measure its mass and width
Dialogue as Moral Paradigm: Paths Toward Intercultural Transformation
The Council of Europeâs 2008 White Paper on Intercultural Dialogue: âliving
together as equals in dignityâ points to the need for shared values upon which intercultural dialogue might rest. In order, however, to overcome the monologic separateness that threatens community, we must educate ourselves to recognize the dialogism of our humanity and to engage in deep encounters with others with a mature skepticism of all dogmatisms, including our own. In order to aid us in reaching the necessary insight, the author calls upon Bakhtinâs ideas of the dialogism of every utterance and of the unity and heteroglossia of language, Gadamerâs hermeneutical experience that shakes us loose from what we think we know, and Levinasâs description of that transcendent ideal of a dialogue beyond reciprocity. These perspectives break open our certainty that tribalism and individualism are fundamental, placing them instead as secondary phenomena that, though
powerful, pronounce neither the initial nor the final word on our life together
A model-independent Dalitz plot analysis of B±âDK± with DâK0Sh+hâ (h=Ï,K) decays and constraints on the CKM angle Îł
A binned Dalitz plot analysis of B ±âDK ± decays, with DâKS0Ï+Ï- and DâKS0K+K-, is performed to measure the CP-violating observables x ± and y ± which are sensitive to the CKM angle Îł. The analysis exploits 1.0 fb -1 of data collected by the LHCb experiment. The study makes no model-based assumption on the variation of the strong phase of the D decay amplitude over the Dalitz plot, but uses measurements of this quantity from CLEO-c as input. The values of the parameters are found to be x -=(0.0±4.3±1.5±0.6)Ă10 -2, y -=(2.7±5.2±0.8±2.3)Ă10 -2, x +=(-10.3±4.5±1.8±1.4)Ă10 -2 and y +=(-0.9±3.7±0.8±3.0)Ă10 -2. The first, second, and third uncertainties are the statistical, the experimental systematic, and the error associated with the precision of the strong-phase parameters measured at CLEO-c, respectively. These results correspond to Îł=(44-38+43)°, with a second solution at ÎłâÎł+180°, and r B=0.07±0.04, where r B is the ratio between the suppressed and favoured B decay amplitudes
Homotopy Theory of Strong and Weak Topological Insulators
We use homotopy theory to extend the notion of strong and weak topological
insulators to the non-stable regime (low numbers of occupied/empty energy
bands). We show that for strong topological insulators in d spatial dimensions
to be "truly d-dimensional", i.e. not realizable by stacking lower-dimensional
insulators, a more restrictive definition of "strong" is required. However,
this does not exclude weak topological insulators from being "truly
d-dimensional", which we demonstrate by an example. Additionally, we prove some
useful technical results, including the homotopy theoretic derivation of the
factorization of invariants over the torus into invariants over spheres in the
stable regime, as well as the rigorous justification of replacing by
and by as is common in the current
literature.Comment: 11 pages, 3 figure
Dynamical Spin Response Functions for Heisenberg Ladders
We present the results of a numerical study of the 2 by L spin 1/2 Heisenberg
ladder. Ground state energies and the singlet-triplet energy gaps for L =
(4-14) and equal rung and leg interaction strengths were obtained in a Lanczos
calculation and checked against earlier calculations by Barnes et al. (even L
up to 12). A related moments technique is then employed to evaluate the
dynamical spin response for L=12 and a range of rung to leg interaction
strength ratios (0 - 5). We comment on two issues, the need for
reorthogonalization and the rate of convergence, that affect the numerical
utility of the moments treatment of response functions.Comment: Revtex, 3 figure
Measurement of the Bs0-Bs0 oscillation frequency ÎŽms in Bs0âDs-(3)Ï decays
The Bs0-Bs0 oscillation frequency ÎŽms is measured with 36 pb-1 of data collected in pp collisions at s=7TeV by the LHCb experiment at the Large Hadron Collider. A total of 1381 Bs0âDs-Ï+ and Bs0âDs-Ï+Ï-Ï + signal decays are reconstructed, with average decay time resolutions of 44 fs and 36 fs, respectively. An oscillation signal with a statistical significance of 4.6Ï is observed. The measured oscillation frequency is ÎŽm s=17.63±0.11(stat)±0.02(syst)ps -1
âDeliberate Preparationâ as an evidence-based focus for primary physical education
There is substantial scientific research suggesting the physical and psychological health benefits of a physically active lifestyle. Consequently, governments worldwide prioritize policies, finances, and resources in healthcare, education, and sports sectors to increase mass participation in physical activity. However, practices in physical activity promotion are often not underpinned by evidence-based standardization that is requisite in other domains of epidemiology. The aim of this article is to examine critically the available scientific research on promoting life-long physical activity participation and to propose an evidence-based model for implementation in school physical education. Reasons are discussed as to why programs that integrate physical, psychological, and behavioral skills have been long acknowledged in physical education and physical activity domains but remain lacking in empirical validation. Finally, future directions are suggested that are required to examine the application of this approach to practice in primary-level physical education
Comparison of Post-Activation Potentiating Stimuli on Jump and Sprint Performance
Post-activation potentiation (PAP) is a phenomenon characterized by improved muscle performance based on the previous contractile activity of the muscle. The purpose of this study was to determine the effect of different potentiating stimuli on jump and sprint performance in 13 resistance trained, college-aged men and women. After determining back squat 1 repetition max, subjects returned for testing on separate days to complete one of four interventions (dynamic resistance, weighted plyometric, isometric, or control) in a randomized order. A standardized warmup was performed, followed by a baseline countermovement jump (CMJ) and 20m sprint. Following warm-up and baseline measurements, subjects performed one of the four experimental conditions. CMJ and 20m sprint measurements were completed again at 20-seconds, 4, 8, 12, 16, and 20-minutes. Results revealed significantly faster 0-20m sprint times (p \u3c .05) at the 4, 8, 12, 16, and 20-minute time points compared to baseline and 20-second time points. Significantly faster 0-20m sprint times (p \u3c .05) were also shown for the squat intervention compared to control at 4-minutes, the plyometric and squat intervention compared to control at 8-minutes, the isometric intervention compared to control at 12 and 16- minutes, and the isometric intervention compared to the squat at 20-minutes. These findings indicate that while all PAP stimuli utilized can be effective at improving sprint performance, specific optimal time points may exist
Multitissue molecular, genomic, and developmental effects of the deepwater horizon oil spill on resident Gulf killifish (Fundulus grandis)
The Deepwater Horizon oil rig disaster resulted in crude oil contamination along the Gulf coast in sensitive estuaries. Toxicity from exposure to crude oil can affect populations of fish that live or breed in oiled habitats as seen following the Exxon Valdez oil spill. In an ongoing study of the effects of Deepwater Horizon crude oil on fish, Gulf killifish (Fundulus grandis) were collected from an oiled site (Grande Terre, LA) and two reference locations (coastal MS and AL) and monitored for measures of exposure to crude oil. Killifish collected from Grande Terre had divergent gene expression in the liver and gill tissue coincident with the arrival of contaminating oil and up-regulation of cytochrome P4501A (CYP1A) protein in gill, liver, intestine, and head kidney for over one year following peak landfall of oil (August 2011) compared to fish collected from reference sites. Furthermore, laboratory exposures of Gulf killifish embryos to field-collected sediments from Grande Terre and Barataria Bay, LA, also resulted in increased CYP1A and developmental abnormalities when exposed to sediments collected from oiled sites compared to exposure to sediments collected from a reference site. These data are predictive of population-level impacts in fish exposed to sediments from oiled locations along the Gulf of Mexico coast. © 2013 American Chemical Society
Absolute luminosity measurements with the LHCb detector at the LHC
Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic ''van der Meer scan'' method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overal precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented
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