Enhanced x-ray emission coinciding with giant radio pulses from the Crab Pulsar.

Giant radio pulses (GRPs) are sporadic bursts emitted by some pulsars that last a few microseconds and are hundreds to thousands of times brighter than regular pulses from these sources. The only GRP-associated emission outside of radio wavelengths is from the Crab Pulsar, where optical emission is enhanced by a few percentage points during GRPs. We observed the Crab Pulsar simultaneously at x-ray and radio wavelengths, finding enhancement of the x-ray emission by 3.8 ± 0.7% (a 5.4σ detection) coinciding with GRPs. This implies that the total emitted energy from GRPs is tens to hundreds of times higher than previously known. We discuss the implications for the pulsar emission mechanism and extragalactic fast radio bursts.

[A randomized controlled study comparing uracil-tegafur (UFT)+tamoxifen (UFT+TAM therapy) with cyclophosphamide+adriamycin+5-fluorouracil (CAF therapy) for women with stage I , II, or IIIa breast cancer with four or more involved nodes in the adjuvant setting].

We performed a controlled study to compare the response to cyclophosphamide (CPA), adriamycin (ADM), and fluorouracil (5-FU) (CAF therapy) with that to uracil-tegafur (UFT) plus tamoxifen (TAM) (UFT+TAM therapy), when given as postoperative adjuvant therapy to women with breast cancer. The patients were registered from September 1991 through February 1995 at 51 institutions in the Kinki district of Japan. All patients had stage I, II, or IIIa breast cancer with four or more lymph-node metastases and underwent mastectomy. CAF therapy and UFT+TAM therapy were started within 4 weeks after surgery. CAF therapy consisted of CPA (100 mg/day) on days 1 to 14, followed by 2 weeks of rest, plus ADM (20 mg/m(2)/day) on days 1 and 8 and 5-FU (300 mg/m(2)/day) on days 1 and 8. A total of 6 courses were delivered. UFT+TAM therapy consisted of 3 years of UFT (400 mg/day) plus TAM (20 mg/day), given daily. CAF therapy and UFT+TAM therapy were each assigned to 82 patients. The 5-year survival rate was significantly higher in the UFT+TAM group (82.1%) than in the CAF group (66.2%; p=0.04, logrank test). The 5-year relapse-free survival rate was higher in the UFT+TAM group (61.8%) than in the CAF group (46.3%; p=0.07, logrank test). As for adverse events, the rates of leukopenia, anorexia, nausea and vomiting, general malaise, and hair loss were lower in the UFT+TAM group than in the CAF group. These results suggest that long-term treatment with UFT+TAM may be a useful alternative adjuvant therapy for the management of breast cancer, especially in elderly patients.

Repeated injections of energy in the first 600 ms of the giant flare of SGR 1806-20.

The massive flare of 27 December 2004 from the soft gamma-ray repeater SGR 1806-20, a possible magnetar, saturated almost all gamma-ray detectors, meaning that the profile of the pulse was poorly characterized. An accurate profile is essential to determine physically what was happening at the source. Here we report the unsaturated gamma-ray profile for the first 600 ms of the flare, with a time resolution of 5.48 ms. The peak of the profile (of the order of 10(7) photons cm(-2) s(-1)) was reached approximately 50 ms after the onset of the flare, and was then followed by a gradual decrease with superposed oscillatory modulations possibly representing repeated energy injections with approximately 60-ms intervals. The implied total energy is comparable to the stored magnetic energy in a magnetar (approximately 10(47) erg) based on the dipole magnetic field intensity (approximately 10(15) G), suggesting either that the energy release mechanism was extremely efficient or that the interior magnetic field is much stronger than the external dipole field.

Cold ions in the hot plasma sheet of Earth's magnetotail.

Most visible matter in the Universe exists as plasma. How this plasma is heated, and especially how the initial non-equilibrium plasma distributions relax to thermal equilibrium (as predicted by Maxwell-Boltzman statistics), is a fundamental question in studies of astrophysical and laboratory plasmas. Astrophysical plasmas are often so tenuous that binary collisions can be ignored, and it is not clear how thermal equilibrium develops for these 'collisionless' plasmas. One example of a collisionless plasma is the Earth's plasma sheet, where thermalized hot plasma with ion temperatures of about 5 x 10(7) K has been observed. Here we report direct observations of a plasma distribution function during a solar eclipse, revealing cold ions in the Earth's plasma sheet in coexistence with thermalized hot ions. This cold component cannot be detected by plasma sensors on satellites that are positively charged in sunlight, but our observations in the Earth's shadow show that the density of the cold ions is comparable to that of hot ions. This high density is difficult to explain within existing theories, as it requires a mechanism that permits half of the source plasma to remain cold upon entry into the hot turbulent plasma sheet.