Powerful extragalactic jets dissipate their kinetic energy far from the central black hole.

Accretion onto the supermassive black hole in some active galactic nuclei (AGN) drives relativistic jets of plasma, which dissipate a significant fraction of their kinetic energy into gamma-ray radiation. The location of energy dissipation in powerful extragalactic jets is currently unknown, with implications for particle acceleration, jet formation, jet collimation, and energy dissipation. Previous studies have been unable to constrain the location between possibilities ranging from the sub-parsec-scale broad-line region to the parsec-scale molecular torus, and beyond. Here we show using a simple diagnostic that the more distant molecular torus is the dominant location for powerful jets. This diagnostic, called the seed factor, is dependent only on observable quantities, and is unique to the seed photon population at the location of gamma-ray emission. Using 62 multiwavelength, quasi-simultaneous spectral energy distributions of gamma-ray quasars, we find a seed factor distribution which peaks at a value corresponding to the molecular torus, demonstrating that energy dissipation occurs  ~1 parsec from the black hole (or  ~104 Schwarzchild radii for a 109M⊙ black hole).

A Competency-Based Curriculum for Critical Care Nurse Practitioners' Transition to Practice.

BACKGROUND: Nearly one-third of new-graduate nurse practitioners report undergoing no formal orientation process, and postcertification orientation processes vary. A validated curriculum would address the need for structured training to enhance new graduates' practice transition. METHODS: A competency-based practice transition curriculum for intensive care unit nurse practitioners was created using a literature review and expert panels. Competencies were established that were based on clinical categories essential to nurse practitioner practice in the intensive care unit and adapted from existing Accreditation Council for Graduate Medical Education training, aligned with the precertification nursing curriculum. Participants recruited from academic and clinical backgrounds were asked to rank curriculum items using a 4-point Likert scale. Competencies were refined on the basis of participants' survey feedback. RESULTS: A total of 31 participants from academic medical centers and schools of nursing throughout the United States responded to the request for competency validation; 29% of participants provided qualitative data. All 9 competency topics received a mean rating greater than 3.5 and were deemed valid. Using the combined quantitative and qualitative data, a final set of competencies for nurse practitioners in the intensive care unit was developed. CONCLUSIONS: The curriculum developed and validated in this study can become the basis for practice transition for novice nurse practitioners. The curriculum is adaptable and can be used for surgical and medical intensive care units. As refined, the competencies provide a validated foundation for training of new-graduate nurse practitioners in the intensive care unit.

A kiloparsec-scale internal shock collision in the jet of a nearby radio galaxy.

Jets of highly energized plasma with relativistic velocities are associated with black holes ranging in mass from a few times that of the Sun to the billion-solar-mass black holes at the centres of galaxies. A popular but unconfirmed hypothesis to explain how the plasma is energized is the 'internal shock model', in which the relativistic flow is unsteady. Faster components in the jet catch up to and collide with slower ones, leading to internal shocks that accelerate particles and generate magnetic fields. This mechanism can explain the variable, high-energy emission from a diverse set of objects, with the best indirect evidence being the unseen fast relativistic flow inferred to energize slower components in X-ray binary jets. Mapping of the kinematic profiles in resolved jets has revealed precessing and helical patterns in X-ray binaries, apparent superluminal motions, and the ejection of knots (bright components) from standing shocks in the jets of active galaxies. Observations revealing the structure and evolution of an internal shock in action have, however, remained elusive, hindering measurement of the physical parameters and ultimate efficiency of the mechanism. Here we report observations of a collision between two knots in the jet of nearby radio galaxy 3C 264. A bright knot with an apparent speed of (7.0 ± 0.8)c, where c is the speed of light in a vacuum, is in the incipient stages of a collision with a slower-moving knot of speed (1.8 ± 0.5)c just downstream, resulting in brightening of both knots--as seen in the most recent epoch of imaging.

Does therapeutic touch help reduce pain and anxiety in patients with cancer?

With more than 10 million patients with cancer in the United States, pain and symptom management is an important topic for oncology nurses. Complementary therapies, such as therapeutic touch, may offer nurses a nonpharmacologic method to ease patients' pain. Using 12 research studies, the authors examined the evidence concerning the effectiveness of this type of treatment in reducing pain and anxiety.