A double peaked pulse profile observed in GX 1+4

The hard X-ray pulsar GX 1+4 was observed several times in the last few years with a pair of balloon-borne Xenon filled Multi-cell Proportional Counters (XMPC). In a balloon flight made on 22 March 1995, the source was detected in a bright state, the average observed source count rate being $8.0\pm0.2/s$ per detector. X-ray pulsations with a period of $121.9\pm0.1$ s were detected in the source with a broad double peak pulse feature. When observed in December 1993 with the same instrument, the pulse profile of GX 1+4 showed a single peak. This change in the pulse profile to a double pulse structure in about 15 months indicates either activation of the opposite pole of the neutron star if the magnetic field is asymmetric or possibly a change in the beam pattern, from a pencil beam to a fan beam. Assuming a fan beam configuration, the pulse profile is used to find the inclinations of the magnetic axis and the viewing axis with the spin axis. The derived angles support the GINGA observations of a dip in the pulse profile which was resolved to have a local maximum in one of the observations and was explained with resonance scattering of cyclotron line energy photons by the accretion column (Makishima et al., \markcite{maki1988}, Dotani et al., \markcite{dotani1989}.). Compared to our previous observation of the same source with the same telescope (Rao et al., \markcite{rao1994}) a period change rate of $0.72 \pm 0.40 s/yr$ is obtained which is the lowest rate of change of period for this source since its discovery. Average pulse fraction in the hard X-ray range is low (30%), consistent with its anti correlation with luminosity as reported by us earlier (Rao et al., \markcite{rao1994}) and the observed spectrum is very hard (power law photon index $1.67\pm0.12$).Comment: 10 pages, to appear in A&

Economic Comparison of Alternatives to Sulfamethazine Use in Pork Production

Sulfamethazinehas been widely used in the production of meat animals. It is effective as a product for treatment as well as prevention of animal disease leading to improved production efficiencies and lower cost meat and meat products. This was true especially in pork production. However, in recent years, use ofsulfamethazine in meat animal production has received a renewed focus. Thisstudy provides an economic analysis ofselected alternatives to the use of sulfamethazine in pork production. Alternatives evaluated were sulfathiazole, oxytetracycline, chlortetracycline, tylosin and lincomycin. Sulfathiazole isshown to be the most cost effective alternative. Production efficiency, production costs, and pork priceswere only slightly impacted when sulfathiazole was substituted for sulfamethazine. Sulfathiazole is followed by lincomycin, then the tetracyclines, and tylosi

Discovery of optical pulsations in V2116 Ophiuchi/GX 1+4

We report the detection of pulsations with $\sim 124$ s period in V2116 Oph, the optical counterpart of the low-mass X-ray binary GX 1+4. The pulsations are sinusoidal with modulation amplitude of up to 4% in blue light and were observed in ten different observing sessions during 1996 April-August using a CCD photometer at the 1.6-m and 0.6-m telescopes of Laborat\'orio Nacional de Astrof\'{\i}sica, in Brazil. The pulsations were also observed with the $UBVRI$ fast photometer. With only one exception the observed optical periods are consistent with those observed by the BATSE instrument on board the Compton Gamma Ray Observatory at the same epoch. There is a definite correlation between the observability of pulsations and the optical brightness of the system: V2116~Oph had $R$ magnitude in the range $15.3-15.5$ when the pulsed signal was detected, and $R = 16.0-17.7$ when no pulsations were present. The discovery makes GX 1+4 only the third of $\sim 35$ accretion-powered X-ray pulsars to be firmly detected as a pulsating source in the optical. The presence of flickering and pulsations in V2116 Oph adds strong evidence for an accretion disk scenario in this system. The absolute magnitude of the pulsed component on 1996 May 27 is estimated to be $M_V \sim -1.5$. The implied dimensions for the emitting region are 1.1 R_{\sun}, 3.2 R_{\sun}, and 7.0 R_{\sun}, for black-body spectral distributions with $T = 10^5$ K, $2 \times 10^4$ K, and $1 \times 10^4$ K, respectively.Comment: 9 pages, 3 figures in PostScript, latex, accepted for publication on the Astrophysical Journal Letter

Sleep During Pregnancy: The nuMoM2b Pregnancy and Sleep Duration and Continuity Study

Study Objectives: To characterize sleep duration, timing and continuity measures in pregnancy and their association with key demographic variables. Methods: Multisite prospective cohort study. Women enrolled in the nuMoM2b study (nulliparous women with a singleton gestation) were recruited at the second study visit (16-21 weeks of gestation) to participate in the Sleep Duration and Continuity substudy. Women <18 years of age or with pregestational diabetes or chronic hypertension were excluded from participation. Women wore a wrist activity monitor and completed a sleep log for 7 consecutive days. Time in bed, sleep duration, fragmentation index, sleep efficiency, wake after sleep onset, and sleep midpoint were averaged across valid primary sleep periods for each participant. Results: Valid data were available from 782 women with mean age of 27.3 (5.5) years. Median sleep duration was 7.4 hours. Approximately 27.9% of women had a sleep duration of 9 hours. In multivariable models including age, race/ethnicity, body mass index, insurance status, and recent smoking history, sleep duration was significantly associated with race/ethnicity and insurance status, while time in bed was only associated with insurance status. Sleep continuity measures and sleep midpoint were significantly associated with all covariates in the model, with the exception of age for fragmentation index and smoking for wake after sleep onset. Conclusions: Our results demonstrate the relationship between sleep and important demographic characteristics during pregnancy

Survival associated with the use of sentinel lymph node in addition to lymphadenectomy in early-stage cervical cancer treated with surgery alone: A sub-analysis of the Surveillance in Cervical CANcer (SCCAN) collaborative study

Aim The aim of this study was to assess whether the use of sentinel lymph node (SLN) in addition to lymphadenectomy was associated with survival benefit in patients with early-stage cervical cancer. Methods International, multicenter, retrospective study. Inclusion criteria: cervical cancer treated between 01/2007 and 12/2016 by surgery only; squamous cell carcinoma, adenocarcinoma, adenosquamous carcinoma, FIGO 2009 stage IB1-IIA2, negative surgical margins, and laparotomy approach. Patients undergoing neo-adjuvant and/or adjuvant treatment and/or with positive para-aortic lymph nodes, were excluded. Women with positive pelvic nodes who refused adjuvant treatment, were included. Lymph node assessment was performed by SLN (with ultrastaging protocol) plus pelvic lymphadenectomy (‘SLN’ group) or pelvic lymphadenectomy alone (‘non-SLN’ group). Results 1083 patients were included: 300 (27.7 %) in SLN and 783 (72.3 %) in non-SLN group. 77 (7.1 %) patients had recurrence (N = 11, 3.7 % SLN versus N = 66, 8.4 % non-SLN, p = 0.005) and 34 (3.1 %) (N = 4, 1.3 % SLN versus N = 30, 3.8 % non-SLN, p = 0.033) died. SLN group had better 5-year disease-free survival (DFS) (96.0 %,95 %CI:93.5–98.5 versus 92.0 %,95 %CI:90.0–94.0; p = 0.024). No 5-year overall survival (OS) difference was shown (98.4 %,95 %CI:96.8–99.9 versus 96.8 %,95 %CI:95.4–98.2; p = 0.160). SLN biopsy and lower stage were independent factors associated with improved DFS (HR:0.505,95 %CI:0.266–0.959, p = 0.037 and HR:2.703,95 %CI:1.389–5.261, p = 0.003, respectively). Incidence of pelvic central recurrences was higher in the non-SLN group (1.7 % versus 4.5 %, p = 0.039). Conclusion Adding SLN biopsy to pelvic lymphadenectomy was associated with lower recurrence and death rate and improved 5-year DFS. This might be explained by the lower rate of missed nodal metastasis thanks to the use of SLN ultrastaging. SLN biopsy should be recommended in patients with early-stage cervical cancer

HETE Observations of the Gamma-Ray Burst GRB030329: Evidence for an Underlying Soft X-ray Component

An exceptionally intense gamma-ray burst, GRB030329, was detected and localized by the instruments on board the High Energy Transient Explorer satellite (HETE) at 11:37:14 UT on 29 March 2003. The burst consisted of two \~10s pulses of roughly equal brightness and an X-ray tail lasting >100s. The energy fluence in the 30-400 keV energy band was 1.08e-4 erg/cm2, making GRB030329 one of the brightest GRBs ever detected. Communication of a 2 arcmin error box 73 minutes after the burst allowed the rapid detection of a counterpart in the optical, X-ray, radio and the ensuing discovery of a supernova with most unusual characteristics. Analyses of the burst lightcurves reveal the presence of a distinct, bright, soft X-ray component underlying the main GRB: the 2-10 keV fluence of this component is ~7e-6 erg/cm2. The main pulses of GRB030329 were preceded by two soft, faint, non-thermal bumps. We present details of the HETE observations of GRB030329.Comment: 22 pages, 5 figures, to be published in ApJ 617, no. 2 (10 December 2004). Referee comments have been incorporated; results of improved spectral analysis are include

The ECLAIRs micro-satellite mission for gamma-ray burst multi-wavelength observations

Gamma-ray bursts (GRB), at least those with a duration longer than a few seconds are the most energetic events in the Universe and occur at cosmological distances. The ECLAIRs micro-satellite, to be launched in 2009, will provide multi-wavelength observations of GRB, to study their astrophysics and to use them as cosmological probes. Furthermore in 2009 ECLAIRs is expected to be the only space borne instrument capable of providing a GRB trigger in near real-time with sufficient localization accuracy for GRB follow-up observations with the powerful ground based spectroscopic telescopes available by then. A "Phase A study" of the ECLAIRs project has recently been launched by the French Space Agency CNES, aiming at a detailed mission design and selection for flight in 2006. The ECLAIRs mission is based on a CNES micro-satellite of the "Myriade" family and dedicated ground-based optical telescopes. The satellite payload combines a 2 sr field-of-view coded aperture mask gamma-camera using 6400 CdTe pixels for GRB detection and localization with 10 arcmin precision in the 4 to 50 keV energy band, together with a soft X-ray camera for onboard position refinement to 1 arcmin. The ground-based optical robotic telescopes will detect the GRB prompt/early afterglow emission and localize the event to arcsec accuracy, for spectroscopic follow-up observations.Comment: 7 pages, 1 figure, proceedings of the conference "New Developments in Photodetection", Beaune (France), June 25005. Submitted to NIM-A (Elsevier Science