Evaluation of a standard provision versus an autonomy promotive exercise referral programme: rationale and study design

Background The National Institute of Clinical Excellence in the UK has recommended that the effectiveness of ongoing exercise referral schemes to promote physical activity should be examined in research trials. Recent empirical evidence in health care and physical activity promotion contexts provides a foundation for testing the utility of a Self Determination Theory (SDT) -based exercise referral consultation. Methods/Design Design: An exploratory cluster randomised controlled trial comparing standard provision exercise on prescription with a Self Determination Theory-based (SDT) exercise on prescription intervention. Participants: 347 people referred to the Birmingham Exercise on Prescription scheme between November 2007 and July 2008. The 13 exercise on prescription sites in Birmingham were randomised to current practice (n=7) or to the SDT-based intervention (n=6). Outcomes measured at 3 and 6-months: Minutes of moderate or vigorous physical activity per week assessed using the 7-day Physical Activity Recall; physical health: blood pressure and weight; health status measured using the Dartmouth CO-OP charts; anxiety and depression measured by the Hospital Anxiety and Depression Scale and vitality measured by the subjective vitality score; motivation and processes of change: perceptions of autonomy support from the advisor, satisfaction of the needs for competence, autonomy, and relatedness via physical activity, and motivational regulations for exercise. Discussion This trial will determine whether an exercise referral programme based on Self Determination Theory increases physical activity and other health outcomes compared to a standard programme and will test the underlying SDT-based process model (perceived autonomy support, need satisfaction, motivation regulations, outcomes) via structural equation modelling. Trial registration The trial is registered as Current Controlled trials ISRCTN07682833

A Measurement of Rb using a Double Tagging Method

The fraction of Z to bbbar events in hadronic Z decays has been measured by the OPAL experiment using the data collected at LEP between 1992 and 1995. The Z to bbbar decays were tagged using displaced secondary vertices, and high momentum electrons and muons. Systematic uncertainties were reduced by measuring the b-tagging efficiency using a double tagging technique. Efficiency correlations between opposite hemispheres of an event are small, and are well understood through comparisons between real and simulated data samples. A value of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is statistical and the second systematic. The uncertainty on Rc, the fraction of Z to ccbar events in hadronic Z decays, is not included in the errors. The dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the deviation of Rc from the value 0.172 predicted by the Standard Model. The result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European Physical Journal

Measurement of the B+ and B-0 lifetimes and search for CP(T) violation using reconstructed secondary vertices

The lifetimes of the B+ and B-0 mesons, and their ratio, have been measured in the OPAL experiment using 2.4 million hadronic Z(0) decays recorded at LEP. Z(0) --> b (b) over bar decays were tagged using displaced secondary vertices and high momentum electrons and muons. The lifetimes were then measured using well-reconstructed charged and neutral secondary vertices selected in this tagged data sample. The results aretau(B+) = 1.643 +/- 0.037 +/- 0.025 pstau(Bo) = 1.523 +/- 0.057 +/- 0.053 pstau(B+)/tau(Bo) = 1.079 +/- 0.064 +/- 0.041,where in each case the first error is statistical and the second systematic.A larger data sample of 3.1 million hadronic Z(o) decays has been used to search for CP and CPT violating effects by comparison of inclusive b and (b) over bar hadron decays, No evidence fur such effects is seen. The CP violation parameter Re(epsilon(B)) is measured to be Re(epsilon(B)) = 0.001 +/- 0.014 +/- 0.003and the fractional difference between b and (b) over bar hadron lifetimes is measured to(Delta tau/tau)(b) = tau(b hadron) - tau((b) over bar hadron)/tau(average) = -0.001 +/- 0.012 +/- 0.008

Male infertility in spinal cord trauma

Every year there are 10 thousand new cases of patients victimized by spinal cord trauma (SCT) in the United States and it is estimated that there are 7 thousand new cases in Brazil. Eighty percent of patients are fertile males. Infertility in this patient group is due to 3 main factors resulting from spinal cord lesions: erectile dysfunction, ejaculatory disorder and low sperm counts. Erectile dysfunction has been successfully treated with oral and injectable medications, use of vacuum devices and penile prosthesis implants. The technological improvement in penile vibratory stimulation devices (PVS) and rectal probe electro-ejaculation (RPE) has made such procedures safer and accessible to patients with ejaculatory dysfunction. Despite the normal number of spermatozoa found in semen of spinal cord-injured patients, their motility is abnormal. This change does not seem to be related to changes in scrotal thermal regulation, frequency of ejaculation or duration of spinal cord damage but to factors related to the seminal plasma. Despite the poor seminal quality, increasingly more men with SCT have become fathers through techniques ranging from simple homologous insemination to sophisticated assisted reproduction techniques such as intracytoplasmic sperm injection (ICSI).Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Department of UrologySan Francisco Home School Section of UrologyUNIFESP, EPM, Department of UrologySciEL

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Litter quality and its response to water level drawdown in boreal peatlands at plant species and community level

Changes in the structure of plant communities may have much more impact on ecosystem carbon (C) cycling than any phenotypic responses to environmental changes. We studied these impacts via the response of plant litter quality, at the level of species and community, to persistent water-level (WL) drawdown in peatlands. We studied three sites with different nutrient regimes, and water-level manipulations at two time scales. The parameters used to characterize litter quality included extractable substances, cellulose, holocellulose, composition of hemicellulose (neutral sugars, uronic acids), Klason lignin, CuO oxidation phenolic products, and concentrations of C and several nutrients. The litters formed four chemically distinct groups: non-graminoid foliar litters, graminoids, mosses and woody litters. Direct effects of WL drawdown on litter quality at the species level were overruled by indirect effects via changes in litter type composition. The pristine conditions were characterized by Sphagnum moss and graminoid litters. Short-term (years) responses of the litter inputs to WL drawdown were small. In longterm (decades), total litter inputs increased, due to increased tree litter inputs. Simultaneously, the litter type composition and its chemical quality at the community level greatly changed. The changes that we documented will strongly affect soil properties and C cycle of peatlands.Peer reviewe

Measurement of the W+W−γW^{+}W^{-} \gamma Cross-section and First direct Limits on Anomalous Electroweak Quartic Gauge Couplings

A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV. From these data, 17 W+W-gamma candidates are selected with photon energy greater than 10GeV, consistent with the Standard Model expectation. These events are used to measure the e+e- to W+W-gamma cross-section within a set of geometric and kinematic cuts; sigma{W+W-gamma} = 136+-37+-8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the {W+ W- gamma gamma} and {W+ W- gamma Z0} vertices: -0.070GeV^{-2} < a_0/Lambda^2 < 0.070GeV^{-2}, -0.13GeV^{-2} < a_c/Lambda^2 < 0.19GeV^{-2}, -0.61GeV^{-2} < a_n/Lambda^2 < 0.57GeV^{-2}, where Lambda represents the energy scale for new physics.A study of W + W − events accompanied by hard photon radiation produced in e + e − collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183 pb −1 of data recorded at s =189 GeV. From these data, 17 W + W − γ candidates are selected with photon energy greater than 10 GeV, consistent with the Standard Model expectation. These events are used to measure the e + e − →W + W − γ cross-section within a set of geometric and kinematic cuts, σ ̂ WW γ =136±37±8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the W + W − γγ and W + W − γ Z 0 vertices: −0.070 GeV −

Transverse and Longitudinal Bose Einstein Correlations in hadronic Z0Z^0 Decays

Bose-Einstein correlations in pairs of identical charged pions produced in asample of 4.3 million Z0 hadronic decays are studied as a function of the threecomponents of the momentum difference, transverse ("out" and "side") andlongitudinal with respect to the thrust direction of the event. A significantdifference between the transverse, r_t_side, and longitudinal, r_l, dimensionsis observed, indicating that the emitting source of identical pions, asobserved in the Longitudinally CoMoving System, has an elongated shape. This isobserved with a variety of selection techniques. Specifically, the values ofthe parameters obtained by fitting the extended Goldhaber parametrisation tothe correlation function C'= C^{DATA}}/C^{MC} for two-jet events, selected withthe Durham algorithm and resolution parameter ycut=0.04, arer_t_out=(0.647+-0.011(stat})+0.022-0.124(syst)) fm,r_t_side=(0.809+-0.009(stat)+0.019-0.032}(syst)) fm, r_l=(0.989+-0.011(stat)+0.030-0.015(syst})) fm andr_l/r_t_side=1.222+- 0.027(stat})+0.075-0.012(syst). The results are discussedin the context of a recent model of Bose-Einstein correlations based on stringfragmentation.Bose-Einstein correlations in pairs of identical charged pions produced in a sample of 4.3 million Z0 hadronic decays are studied as a function of the three components of the momentum difference, transverse ("out" and "side") and longitudinal with respect to the thrust direction of the event. A significant difference between the transverse, r_t_side, and longitudinal, r_l, dimensions is observed, indicating that the emitting source of identical pions, as observed in the Longitudinally CoMoving System, has an elongated shape. This is observed with a variety of selection techniques. Specifically, the values of the parameters obtained by fitting the extended Goldhaber parametrisation to the correlation function C'= C^{DATA}}/C^{MC} for two-jet events, selected with the Durham algorithm and resolution parameter ycut=0.04, are r_t_out=(0.647+-0.011(stat})+0.022-0.124(syst)) fm, r_t_side=(0.809+-0.009(stat)+0.019-0.032}(syst)) fm, r_l=(0.989+-0.011(stat)+0.030-0.015(syst})) fm and r_l/r_t_side=1.222+-0.027(stat})+0.075-0.012(syst). The results are discussed in the context of a recent model of Bose-Einstein correlations based on string fragmentation

Experimental properties of gluon and quark jets from a point source

Gluon jets are identified in hadronic Z0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted intervals of rapidity. For soft particles at large transverse momentum, we observe the charged particle multiplicity ratio of gluon to quark jets to be 2.29 +- 0.09 +- 0.15 in agreement with the prediction that this ratio should approximately equal the ratio of QCD color factors, CA/CF = 2.25. The intervals used to define soft particles and large transverse momentum for this result, p<4 GeV/c and 0.8<p_t<3.0 GeV/c, are motivated by the predictions of the Herwig Monte Carlo multihadronic event generator. Additionally, our gluon jet data allow a sensitive test of the phenomenon of non-leading QCD terms known as color reconnection. We test the model of color reconnection implemented in the Ariadne Monte Carlo multihadronic event generator and find it to be disfavored by our data.Gluon jets are identified in hadronic Z0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted intervals of rapidity. For soft particles at large transverse momentum, we observe the charged particle multiplicity ratio of gluon to quark jets to be 2.29 +- 0.09 +- 0.15 in agreement with the prediction that this ratio should approximately equal the ratio of QCD color factors, CA/CF = 2.25. The intervals used to define soft particles and large transverse momentum for this result, p<4 GeV/c and 0.8<p_t<3.0 GeV/c, are motivated by the predictions of the Herwig Monte Carlo multihadronic event generator. Additionally, our gluon jet data allow a sensitive test of the phenomenon of non-leading QCD terms known as color reconnection. We test the model of color reconnection implemented in the Ariadne Monte Carlo multihadronic event generator and find it to be disfavored by our data.Gluon jets are identified in hadronic Z0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted intervals of rapidity. For soft particles at large transverse momentum, we observe the charged particle multiplicity ratio of gluon to quark jets to be 2.29 +- 0.09 +- 0.15 in agreement with the prediction that this ratio should approximately equal the ratio of QCD color factors, CA/CF = 2.25. The intervals used to define soft particles and large transverse momentum for this result, p<4 GeV/c and 0.8<p_t<3.0 GeV/c, are motivated by the predictions of the Herwig Monte Carlo multihadronic event generator. Additionally, our gluon jet data allow a sensitive test of the phenomenon of non-leading QCD terms known as color reconnection. We test the model of color reconnection implemented in the Ariadne Monte Carlo multihadronic event generator and find it to be disfavored by our data.Gluon jets are identified in hadronic Z0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted intervals of rapidity. For soft particles at large transverse momentum, we observe the charged particle multiplicity ratio of gluon to quark jets to be 2.29 +- 0.09 +- 0.15 in agreement with the prediction that this ratio should approximately equal the ratio of QCD color factors, CA/CF = 2.25. The intervals used to define soft particles and large transverse momentum for this result, p<4 GeV/c and 0.8<p_t<3.0 GeV/c, are motivated by the predictions of the Herwig Monte Carlo multihadronic event generator. Additionally, our gluon jet data allow a sensitive test of the phenomenon of non-leading QCD terms known as color reconnection. We test the model of color reconnection implemented in the Ariadne Monte Carlo multihadronic event generator and find it to be disfavored by our data

τ\tau decays with neutral kaons

The branching ratio of the tau lepton to a neutral K meson is measured from a sample of approximately 200,000 tau decays recorded by the OPAL detector at centre-of-mass energies near the Z0 resonance. The measurement is based on two samples which identify one-prong tau decays with KL and KS mesons. The combined branching ratios are measured to be B(tau- -->pi- K0bar nutau) = (9.33+-0.68+-0.49)x10^-3 B(tau- -->pi- K0bar [>=1pi0] nutau) = (3.24+-0.74+-0.66)x10^-3 B(tau- -->K- K0bar [>=0pi0] nutau) = (3.30+-0.55+-0.39)x10^-3 where the first error is statistical and the second systematic.The branching ratio of the tau lepton to a neutral K meson is measured from a sample of approximately 200,000 tau decays recorded by the OPAL detector at centre-of-mass energies near the Z0 resonance. The measurement is based on two samples which identify one-prong tau decays with KL and KS mesons. The combined branching ratios are measured to be B(tau- -->pi- K0bar nutau) = (9.33+-0.68+-0.49)x10^-3 B(tau- -->pi- K0bar [>=1pi0] nutau) = (3.24+-0.74+-0.66)x10^-3 B(tau- -->K- K0bar [>=0pi0] nutau) = (3.30+-0.55+-0.39)x10^-3 where the first error is statistical and the second systematic