The local Galactic magnetic field in the direction of Geminga

The Milagro hot spot A, close to the Galactic anticenter direction, has been tentatively attributed to cosmic rays from a local reservoir (at a distance ~100 pc), freely streaming along diverging and smooth magnetic field lines. This is at variance with the geometry of the ~kpc scale Galactic magnetic field, which is known to be aligned with the spiral arms. We investigate the information available on the geometry of the magnetic field on the scales (~100 pc) of relevance here. The magnetic field immediately upstream of the heliosphere has been investigated by previous authors by modeling the interaction of this field with the solar wind. At larger distances, we use the dispersion measure and the rotation measure of nearby pulsars (especially towards the third Galactic quadrant). Additional information about the local field towards the North Polar Spur is taken from previous studies of the diffuse radio emission and the polarization of starlight. The asymmetry of the heliosphere with respect to the incoming interstellar medium implies a magnetic field almost orthogonal to the local spiral arm, in the general direction of hot spot A, but more to the south. This is in good agreement with the nearby pulsar data on the one side, and the North Polar Spur data on the other. The local magnetic field on scales of ~100 parsecs around the Sun seems to be oriented so as to provide a direct connection between the Solar system and a possible site of the Geminga supernova; the residual angular difference and the shape and orientation of the Milagro hot spot can be attributed to the field trailing in the wake of the heliosphere.Comment: 5 pages, 3 figures, accepted for publication in Astronomy and Astrophysic

X-ray pulsations from the radio-quiet gamma-ray pulsar in CTA 1

Prompted by the Fermi LAT discovery of a radio-quiet gamma-ray pulsar inside the CTA 1 supernova remnant, we obtained a 130 ks XMM-Newton observation to assess the timing behavior of this pulsar. Exploiting both the unprecedented photon harvest and the contemporary Fermi LAT timing measurements, a 4.7 sigma single peak pulsation is detected, making PSR J0007+7303 the second example, after Geminga, of a radio-quiet gamma-ray pulsar also seen to pulsate in X-rays. Phase-resolved spectroscopy shows that the off-pulse portion of the light curve is dominated by a power-law, non-thermal spectrum, while the X-ray peak emission appears to be mainly of thermal origin, probably from a polar cap heated by magnetospheric return currents, pointing to a hot spot varying throughout the pulsar rotation.Comment: 19 pages, 4 figures. Accepted for publication in ApJ Letter

XMM-Newton and VLT observations of the isolated neutron star 1E 1207.4-5209

In August 2002, XMM-Newton devoted two full orbits to the observation of 1E 1207.4-5209, making this isolated neutron star the most deeply scrutinized galactic target of the mission. Thanks to the high throughput of the EPIC instrument, ~360,000 photons were collected from the source, allowing for a very sensitive study of the temporal and spectral behaviour of this object. The spectral data, both time-averaged and phase-resolved, yield one compelling interpretation of the observed features: cyclotron absorption from one fundamental (~0.7 keV) and three harmonics, at ~1.4, ~2.1 and ~2.8 keV. Possible physical consequences are discussed, also on the basis of the obvious phase variations of the features' shapes and depths. We also present deep VLT optical data which we have used to search for a counterpart, with negative results down to ~27.Comment: 25 pages, 9 postscript figures. Accepted for publication in Astronomy & Astrophysic

Installation and data analysis of a small network of SAR corner reflectors in Fogo, Cape Verde

Since early ninety’s Synthetic Aperture Radar Interferometry (InSAR) has been exploited for geophysical applications. InSAR technique is capable to capture information on surface deformation and can be a useful tool for monitoring active seismic and volcanic areas. Despite the capability of SAR sensors to operate in all weather and day/night conditions, SAR signal is affected by different source of noise (e.g. water vapour or instrumental noise) [Hanssen, 2001]. These disturbing sources affect the accuracy of InSAR deformation map, especially for time series analysis, and the quality control of InSAR measurements, either standard differential interferometry and Persistent Scatterers Interferometry (PSI), is not an easy task. A fruitful solution is represented by the adoption of passive Corner Reflectors (CRs). CRs can provide point measurements with high level of confidence with sub-centimeter accuracy [Marinkovic et al, 2007], thanks to their high backscattered signal value, and representing strong persistent scatterers to be used for calibrating and validating SAR (from InSAR and PSI technique) deformation map. Indeed, CRs can maintain their interferometric phase stable during time. Additionally, CRs can also be exploited to calibrate the amplitude SAR signal, and to provide reference points for geocoding purposes. Here we present the design, realization and installation of a small CRs network on the Fogo Volcano island, Cape Verde. This activity has been done in the framework of the European project MIAVITA, MItigate and Assess risk from Volcanic Impact on Terrain and human Activities

Sexual and marital trajectories and HIV infection among ever-married women in rural Malawi.

OBJECTIVE: To explore how sexual and marital trajectories are associated with HIV infection among ever-married women in rural Malawi. METHODS: Retrospective survey data and HIV biomarker data for 926 ever-married women interviewed in the Malawi Diffusion and Ideational Change Project were used. The associations between HIV infection and four key life course transitions considered individually (age at sexual debut, premarital sexual activity, entry into marriage and marital disruption by divorce or death) were examined. These transitions were then sequenced to construct trajectories that represent the variety of patterns in the data. The association between different trajectories and HIV prevalence was examined, controlling for potentially confounding factors such as age and region. RESULTS: Although each life course transition taken in isolation may be associated with HIV infection, their combined effect appeared to be conditional on the sequence in which they occurred. Although early sexual debut, not marrying one's first sexual partner and having a disrupted marriage each increased the likelihood of HIV infection, their risk was not additive. Women who both delayed sexual debut and did not marry their first partner are, once married, more likely to experience marital disruption and to be HIV-positive. Women who marry their first partner but who have sex at a young age, however, are also at considerable risk. CONCLUSIONS: These findings identify the potential of a life course perspective for understanding why some women become infected with HIV and others do not, as well as the differentials in HIV prevalence that originate from the sequence of sexual and marital transitions in one's life. The analysis suggests, however, the need for further data collection to permit a better examination of the mechanisms that account for variations in life course trajectories and thus in lifetime probabilities of HIV infection

Long-term placement of continuous popliteal nerve block catheter for management of a wounded patient in a combat field environment: A case report

Continuous peripheral nerve block is a relevant part of multimodal treatment of postoperative pain. In this context the continuous popliteal nerve block is described as an option for postoperative pain management for surgical procedures on the leg, and particularly on the ankle and foot. We applied continuous popliteal nerve block for different types of anesthesia and postoperative pain management via the same catheter. No clear evidence of this specific use has been described in the literature. A 38 year-old patient wounded in combat with a displaced fracture of left tibia and extensive loss of substance needed orthopedic surgeries as well as several reconstructive procedures. A continuous popliteal nerve block was applied via ultrasound-guided catheter for anesthesia at different times, and postoperative pain control for all surgical procedures. The continuous popliteal nerve block and its long-term positioning, of non-common evidence in literature, was utilized to treat a poly-traumatized patient, thereby avoiding repeated general anesthesia and opioid use and their adverse effects. This technique, within a complicated combat field environment, was demonstrated to be clinically effective with high patient satisfaction

Enhancement of adventitious root differentiation and growth of in vitro grapevine shoots inoculated with plant growth promoting rhizobacteria

The effect of Burkholderia spp. strain IF25 on adventitious rooting was evaluated in micropropagated grapevine explants. Data on rooting time, stem length, number of stem nodes, basal callus development, number of roots and root length per rooted microcutting were detected at 6, 8, 10, 13, 19, 26 and 30 days after bacterial inoculation. Results suggest that bacterization of in vitro grapevine explants by strain IF25 affected root differentiation, as the earliest rooting occurred in inoculated shoots, whether or not exogenous IBA had been applied, and increased the average number of roots per explant

Search for periodicities near 59 s in the COS-B gamma-ray data of 2CG195+04 (Geminga)

The COS-B data relating to five observations in the general direction of Geminga, spanning 6.7 years, were searched for pulsation near 59 s. The SAS-2 indication is not confirmed. An indication of a 59 s pulsation in the gamma ray emission from 2CG195+04 (Geminga) was reported. Early analysis of COS-B data supported the result while later improved statistics did not confirm it. Subsequently, detection of a 59 s pulsation in the emission from the direction of Geminga at ultra high gamma and X-rays was reported. Geminga was identified with the X-ray source 1E0630+128. The final COS-B data on Geminga which was observed five times for a total of 214 days are reported