The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10(19) eV, consistent with the expected cutoff energy. We observe the ankle of the cosmic-ray energy spectrum as well, at an energy of 4 x 10(18) eV. We describe the experiment, data collection, and analysis and estimate the systematic uncertainties. The results are presented and the calculation of the statistical significance of our observation is described.

We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (X(max)), for air shower events collected by the High-Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d/d[log(E)] of 47.9+/-6.0(stat)+/-3.2(syst) g/cm2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4x10(18) eV.

Objective: We sought to determine whether patients or their families could identify adverse events in the emergency department (ED), to characterize patient reports of errors and to compare patient reports to events recorded by health care providers. Methods: This was a prospective cohort study in a quaternary care inner city teaching hospital with approximately 40 000 annual visits. ED patients were recruited for participation in a standardized interview within 24 hours of ED discharge and a follow-up interview 3-7 days after discharge. Responses regarding events were tabulated and compared with physician and nurse notations in the medical record and hospital event reporting system. Results: Of 292 eligible patients, 201 (69%) were interviewed within 24 hours of ED discharge, and 143 (71% of interviewees) underwent a follow-up interview 3-7 days after discharge. Interviewees did not differ from the base ED population in terms of age, sex or language. Analysis of patient interviews identified 10 adverse events (5% incident rate; 95% confidence interval [CI] 2.41%-8.96%), 8 near misses (4% incident rate; 95% CI 1.73%-7.69%) and no medical errors. Of the 10 adverse events, 6 (60%) were characterized as preventable (2 raters; κ = 0.78, standard error [SE] 0.20; 95% CI 0.39-1.00; p = 0.01). Adverse events were primarily related to delayed or inadequate analgesia. Only 4 out of 8 (50%) near misses were intercepted by hospital personnel. The secondary interview elicited 2 out of 10 adverse events and 3 out of 8 near misses that had not been identified in the primary interview. No designation (0 out of 10) of an adverse event was recorded in the ED medical record or in the confidential hospital event reporting system. Conclusion: ED patients can identify adverse events affecting their care. Moreover, many of these events are not recorded in the medical record. Engaging patients and their family members in identification of errors may enhance patient safety. RÉSUMÉObjectif : Nous avons cherché à déterminer si les patients ou leurs familles pouvaient détecter des événements indésirables à l'urgence, à caractériser les rapports d'erreurs des patients et à comparer les rapports des patients aux événements consignés par les fournisseurs de soins de santé. Méthodes : Nous avons réalisé une étude de cohorte prospective dans un hôpital universitaire de soins quaternaires du centre-ville qui compte environ 40 000 visites annuellement. Nous avons recruté des patients à l'urgence pour participer à une entrevue normalisée dans les 24 heures suivant ORIGINAL RESEARCH • RECHERCHE ORIGINALE EM ADVANCES