1,214 research outputs found

    Measurement of 25Mg(p; gamma)26Al resonance strengths via gamma spectrometry

    Full text link
    The COMPTEL instrument performed the first mapping of the 1.809 MeV photons in the Galaxy, triggering considerable interest in determing the sources of interstellar 26Al. The predicted 26Al is too low compared to the observation, for a better understanding more accurate rates for the 25Mg(p; gamma)26Al reaction are required. The 25Mg(p;gamma)26Al reaction has been investigated at the resonances at Er= 745; 418; 374; 304 keV at Ruhr-Universitat-Bochum using a Tandem accelerator and a 4piNaI detector. In addition the resonance at Er = 189 keV has been measured deep underground laboratory at Laboratori Nazionali del Gran Sasso, exploiting the strong suppression of cosmic background. This low resonance has been studied with the 400 kV LUNA accelerator and a HPGe detector. The preliminary results of the resonance strengths will be reported.Comment: Accepted for publication in Journal of Physics

    Reproduction, growth and migrations of sei whales Balaenoptera borealis off the west coast of South Africa

    Get PDF
    Results of the examination of 1 062 sei whales Balaenoptera borealis landed at the whaling station at Donkergat, Saldanha Bay, South Africa, in the 1962 and 1963 whaling seasons are presented. Sei whales were usually encountered off the edge of the continental shelf, with males being caught closer inshore than females and mature females furthest of all from the station. Females reached puberty at an average length of 46.1 ft (14.1 m) and an age of 8.2 (95% CI = 7.3, 9.0) years (assuming one growth layer group is formed in the ear plug per year). Males reached sexual maturity at an average length of 45.3 ft (13.8 m) and an age of 8.6 (95% CI = 7.8, 9.4) years. Mean lengths at which growth ceased were 52 ft (15.8 m) in females and 48.6 ft (14.8 m) in males. Most (~90%) conceptions occurred over a 70-day period with a peak in June, and primigravid females conceived six days later than multigravid females. Observed pregnancy rates were as high as 86.1%, but with ovulation rates averaging only 0.47 a year, the catch could not have been fully representative of the population. There was no significant decline in the observed pregnancy rate with age. During the northward migration (May–July), fewer whales were taken in water shallower than 2 000 m than in the southern migration, and the catch was largely composed of immatures. The few adult males taken at that time of year had significantly heavier testes than males of an equivalent size on the southern migration. The southward migration (August–October) was markedly structured, such that pregnant females and immatures of both sexes were in the vanguard, followed by mature males and lastly lactating females and calves. The availability of sei whales off Donkergat declined rapidly from 1965 to 1967, following an episode of massive catching by pelagic whalers in higher latitudes. Keywords: growth, migration, reproduction, sei whales, South AfricaAfrican Journal of Marine Science 2002, 24: 111–13

    CO(4-3) and dust emission in two powerful high-z radio galaxies, and CO lines at high redshifts

    Get PDF
    We report the detection of sub-mm emission from dust at 850 microns and of the 12CO J=4-3 line in the two distant powerful radio galaxies 4C 60.07 (z=3.79) and 6C 1909+722 (z=3.53). In the case of 4C 60.07 the dust emission is also detected at 1.25 mm. The estimated molecular gas masses are large, of the order of ~(0.5-1)x10^{11} Solar. The large FIR luminosities (L_fir ~ 10^{13} Solar) suggest that we are witnessing two major starburst phenomena, while the observed large velocity widths (FWHM > 500 km/sec) are characteristic of mergers. In the case of 4C 60.07 the CO emission extends over ~30 kpc and spans a velocity range of >1000 km/sec. It consists of two distinct features with FWHM of >= 550 km/sec and ~150 km/sec and line centers separated by >=700 km/sec The least massive of these components is probably very gas-rich with potentially >=60% of its dynamical mass in the form of molecular gas. The extraordinary morphology of the CO emission in this object suggests that it is not just a scaled-up version of a local Ultra Luminous Infrared Galaxy, and it may be a formative stage of the elliptical host of the residing radio-loud AGN. Finally we briefly explore the effects of the wide range of gas excitation conditions expected for starburst environments on the luminosity of high-J CO lines. We conclude that in unlensed objects, CO (J+1-->J), J+1>3 lines can be significantly weak with respect to CO J=1-0 and this can hinder their detection even in the presence of substantial molecular gas masses.Comment: 34 pages, 5 figures, accepted for publication in The Astrophysical Journa

    Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction

    Get PDF
    We present evidence for the flavor-changing neutral current decay BK+B\to K^*\ell^+\ell^- and a measurement of the branching fraction for the related process BK+B\to K\ell^+\ell^-, where +\ell^+\ell^- is either an e+ee^+e^- or μ+μ\mu^+\mu^- pair. These decays are highly suppressed in the Standard Model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123×106123\times 10^6 Υ(4S)BBˉ\Upsilon(4S)\to B\bar{B} decays collected with the Babar detector at the PEP-II e+ee^+e^- storage ring. Averaging over K()K^{(*)} isospin and lepton flavor, we obtain the branching fractions B(BK+)=(0.650.13+0.14±0.04)×106{\mathcal B}(B\to K\ell^+\ell^-)=(0.65^{+0.14}_{-0.13}\pm 0.04)\times 10^{-6} and B(BK+)=(0.880.29+0.33±0.10)×106{\mathcal B}(B\to K^*\ell^+\ell^-)=(0.88^{+0.33}_{-0.29}\pm 0.10)\times 10^{-6}, where the uncertainties are statistical and systematic, respectively. The significance of the BK+B\to K\ell^+\ell^- signal is over 8σ8\sigma, while for BK+B\to K^*\ell^+\ell^- it is 3.3σ3.3\sigma.Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let

    Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays

    Get PDF
    We present measurements of the branching fractions for the three-body decays B0 -> D(*)-/+ K0 pi^+/-andtheirresonantsubmodes and their resonant submodes B0 -> D(*)-/+ K*+/- using a sample of approximately 88 million BBbar pairs collected by the BABAR detector at the PEP-II asymmetric energy storage ring. We measure: B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4} B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4} From these measurements we determine the fractions of resonant events to be : f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) = 0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let

    Measurement of the Branching Fraction for B- --> D0 K*-

    Get PDF
    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

    Predicting the seasonal evolution of southern African summer precipitation in the DePreSys3 prediction system

    Get PDF
    We assess the ability of the DePreSys3 prediction system to predict austral summer precipitation (DJF) over southern Africa, defined as the African continent south of 15°S. DePresys3 is a high resolution prediction system (at a horizontal resolution of ~ 60 km in the atmosphere in mid-latitudes and of the quarter degree in the Ocean) and spans the long period 1959–2016. We find skill in predicting interannual precipitation variability, relative to a long-term trend; the anomaly correlation skill score over southern Africa is greater than 0.45 for the first summer (i.e. lead month 2–4), and 0.37 over Mozambique, Zimbabwe and Zambia for the second summer (i.e. lead month 14–16). The skill is related to the successful prediction of the El-Nino Southern Oscillation (ENSO), and the successful simulation of ENSO teleconnections to southern Africa. However, overall skill is sensitive to the inclusion of strong La-Nina events and also appears to change with forecast epoch. For example, the skill in predicting precipitation over Mozambique is significantly larger for the first summer in the 1990–2016 period, compared to the 1959–1985 period. The difference in skill in predicting interannual precipitation variability over southern Africa in different epochs is consistent with a change in the strength of the observed teleconnections of ENSO. After 1990, and consistent with the increased skill, the observed impact of ENSO appears to strengthen over west Mozambique, in association with changes in ENSO related atmospheric convergence anomalies. However, these apparent changes in teleconnections are not captured by the ensemble-mean predictions using DePreSys3. The changes in the ENSO teleconnection are consistent with a warming over the Indian Ocean and modulation of ENSO properties between the different epochs, but may also be associated with unpredictable atmospheric variability

    Measurement of the B+ --> p pbar K+ Branching Fraction and Study of the Decay Dynamics

    Get PDF
    With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar. We measure a branching fraction Br(B+ --> p pbar K+)=(6.7+/-0.5+/-0.4)x10^{-6}. An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level.Comment: 8 pages, 7 postscript figures, submitted to Phys. Rev. D (Rapid Communications

    Search for rare quark-annihilation decays, B --> Ds(*) Phi

    Full text link
    We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications

    The effects of integrated care: a systematic review of UK and international evidence

    Get PDF
    BACKGROUND: Healthcare systems around the world have been responding to the demand for better integrated models of service delivery. However, there is a need for further clarity regarding the effects of these new models of integration, and exploration regarding whether models introduced in other care systems may achieve similar outcomes in a UK national health service context. METHODS: The study aimed to carry out a systematic review of the effects of integration or co-ordination between healthcare services, or between health and social care on service delivery outcomes including effectiveness, efficiency and quality of care. Electronic databases including MEDLINE; Embase; PsycINFO; CINAHL; Science and Social Science Citation Indices; and the Cochrane Library were searched for relevant literature published between 2006 to March 2017. Online sources were searched for UK grey literature, and citation searching, and manual reference list screening were also carried out. Quantitative primary studies and systematic reviews, reporting actual or perceived effects on service delivery following the introduction of models of integration or co-ordination, in healthcare or health and social care settings in developed countries were eligible for inclusion. Strength of evidence for each outcome reported was analysed and synthesised using a four point comparative rating system of stronger, weaker, inconsistent or limited evidence. RESULTS: One hundred sixty seven studies were eligible for inclusion. Analysis indicated evidence of perceived improved quality of care, evidence of increased patient satisfaction, and evidence of improved access to care. Evidence was rated as either inconsistent or limited regarding all other outcomes reported, including system-wide impacts on primary care, secondary care, and health care costs. There were limited differences between outcomes reported by UK and international studies, and overall the literature had a limited consideration of effects on service users. CONCLUSIONS: Models of integrated care may enhance patient satisfaction, increase perceived quality of care, and enable access to services, although the evidence for other outcomes including service costs remains unclear. Indications of improved access may have important implications for services struggling to cope with increasing demand. TRIAL REGISTRATION: Prospero registration number: 42016037725
    corecore