A mildly relativistic radio jet from the otherwise normal type Ic supernova 2007gr.

The class of type Ic supernovae have drawn increasing attention since 1998 owing to their sparse association (only four so far) with long duration gamma-ray bursts (GRBs). Although both phenomena originate from the core collapse of a massive star, supernovae emit mostly at optical wavelengths, whereas GRBs emit mostly in soft gamma-rays or hard X-rays. Though the GRB central engine generates ultra-relativistic jets, which beam the early emission into a narrow cone, no relativistic outflows have hitherto been found in type Ib/c supernovae explosions, despite theoretical expectations and searches. Here we report radio (interferometric) observations that reveal a mildly relativistic expansion in a nearby type Ic supernova, SN 2007gr. Using two observational epochs 60 days apart, we detect expansion of the source and establish a conservative lower limit for the average apparent expansion velocity of 0.6c. Independently, a second mildly relativistic supernova has been reported. Contrary to the radio data, optical observations of SN 2007gr indicate a typical type Ic supernova with ejecta velocities approximately 6,000 km s(-1), much lower than in GRB-associated supernovae. We conclude that in SN 2007gr a small fraction of the ejecta produced a low-energy mildly relativistic bipolar radio jet, while the bulk of the ejecta were slower and, as shown by optical spectropolarimetry, mildly aspherical.

An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20.

Soft gamma-ray repeaters (SGRs) are 'magnetars', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B approximately 10(15) gauss (refs 1 , 2 -3). On 27 December 2004, a giant flare was detected from the magnetar SGR 1806-20 (ref. 2), only the third such event recorded. This burst of energy was detected by a variety of instruments and even caused an ionospheric disturbance in the Earth's upper atmosphere that was recorded around the globe. Here we report the detection of a fading radio afterglow produced by this outburst, with a luminosity 500 times larger than the only other detection of a similar source. From day 6 to day 19 after the flare from SGR 1806-20, a resolved, linearly polarized, radio nebula was seen, expanding at approximately a quarter of the speed of light. To create this nebula, at least 4 x 10(43) ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles.

Subcutaneous primitive neuroectodermal tumour in the abdominal wall of a child: long-term survival after local excision.

Tumours of the peripheral primitive neuroectodermal tumour/Ewing's sarcoma (PNET/ES) family can rarely occur as primary lesions within the skin and subcutis. We present a case of subcutaneous PNET within the abdominal wall of a 33-month-old child. Histologically it was a small round cell tumour that marked strongly for CD99 and displayed ultrastructual evidence of neural differentiation. The tumour was completely excised, but due to an initial misdiagnosis no adjuvant therapy was given. Despite this, the patient is well without evidence of disease 10 years and 3 months after surgery. A review of similar cases reveals not all patients are as fortunate, suggesting combination therapy, including chemotherapy, is still the best treatment for these tumours, even when small and superficial. Our report therefore highlights the importance of recognising PNET/ES in the skin and subcutis so appropriate therapy can be administered.

Intraductal carcinoma of the prostate metastatic to the penile urethra: a rare demonstration of two morphologic patterns of tumor growth.

Penile metastases from prostate cancer are rare and are usually a manifestation of wide-spread cancer dissemination. Isolated urethral metastases form a small fraction of these cases, have a longer survival rate and may represent spread by implantation following instrumentation. We report a case of prostatic carcinoma presenting with an isolated metastasis to the penile urethra after catheterisation and transurethral prostatectomy. The primary tumor had a prominent intraductal component whose architectural features were mimicked in the metastasis. The possible mechanisms of spread and the diverse appearances of cancer associated with an intraductal component are discussed.

Racial disparity in pregnancy outcomes: analysis of black and white teenage pregnancies.

The pregnancies of black women are complicated by adverse outcomes such as prematurity and low birth weight at twice the rate of complications in pregnancies of white women. Although the cause of this racial disparity is unknown, it is most likely multifactorial. The disparity in outcomes has been found in many studies despite implementation of controls for the factors of age, socioeconomic status, and access to health care. We hypothesized that the increased incidence of adverse outcomes may be strongly affected by adequacy of prenatal care. We investigated the effects of comprehensive prenatal care delivered at the University of North Carolina-Chapel Hill Teenage Obstetric Clinic. The gestational age at the onset of prenatal care and the mean number of prenatal visits were the same for black and white teenagers. Among 183 teenagers we found no significant difference between black and white pregnancies for the outcomes of premature labor, premature delivery, fetal death, neonatal mortality, or hypertensive diseases. The mean gestational age at delivery was 38.3 weeks and 39.1 weeks for black and white women, respectively. The mean birth weight was 3126 gm and 3272 gm for black and white women, respectively. There was a trend (p < 0.09) toward more low birth weight infants in white women: 7% for black infants and 12% for white infants. We believe that comprehensive prenatal care significantly lessens the racial disparity in pregnancy outcomes between black and white adolescent women.

Cytologic demonstration of "dysplastic" follicular dendritic cells in a case of hyaline-vascular Castleman's disease.

Large atypical follicular dendritic cells, considered dysplastic by some authors, were first described in association with Castleman's disease in 1991, but until now there has been no cytologic account regarding these cells. We report the cytologic and histologic findings of a case of hyaline-vascular Castleman's disease associated with "dysplastic "follicular dendritic cells which presented as a mediastinal mass in a young man. The presence of giant cells within the preoperative fine-needle aspirate specimen caused initial diagnostic uncertainty and their true nature was only confirmed retrospectively following application of an immunostain for CD21 to direct smears. Awareness of "dysplastic" follicular dendritic cells within aspirates of Castleman's disease will result in less cytological confusion in the future and may help to avoid the possibility of misdiagnosing Hodgkin's lymphoma which has certain cytologic similarities.

Can a postgraduate course for general practitioners deliver perceived benefit for learners, patients and the NHS?: a qualitative study.

The focus of continuing professional development in general practice is shifting towards professional development and away from following personal areas of interest. Previous work has suggested that much CPD has not had an obvious impact in the three areas of professional development: the needs of individual doctors, patients and the needs of the NHS. We report on the results of a programme of study where developments in all three were perceived as being achieved. This outcome was realized by basing learning around real problems course members encountered in their daily work, using these real situations to identify theory, then reinforcing this learning through practical application.

Bidirectional motion observed in the compact symmetric object 1946+708.

We present the first direct measurements of bidirectional motions in an extragalactic radio jet. The radio source 1946+708 is a compact symmetric object with striking S-symmetry identified with a galaxy at a redshift of 0.101. From observations 2 years apart we have determined the velocities of four compact components in the jet, the fastest of which has an apparent velocity of 1.09 h-1c. By pairing up the components, assuming they were simultaneously ejected in opposite directions, we derive a 1 lower limit on the Hubble constant, H0 > 42 km.s-1.Mpc-1.

Limits on the cosmological abundance of supermassive compact objects from a search for multiple imaging in compact radio sources.

Using very long baseline interferometry we have searched a sample of 300 compact radio sources for examples of multiple imaging produced by gravitational lensing; no multiple images were found with separations in the angular range 1.5--50 milliarcsec. This null result allows us to place a limit on the cosmological abundance of intergalactic supermassive compact objects in the mass range approximately 10(6)M( middle dot in circle) to approximately 10(8)M( middle dot in circle); such objects cannot make up more than approximately 1% of the closure density ( 95% confidence). A uniformly distributed population of supermassive black holes forming soon after the big bang does not, therefore, contribute significantly to the dark matter content of the Universe.