Observations of the globular clusters NGC 6388 and M 15 were carried out by the H.E.S.S. array of Cherenkov telescopes for a live time of 27.2 and 15.2 hours respectively. No gamma-ray signal is ...found at the nominal target position of NGC 6388 and M 15. In the primordial formation scenario, globular clusters are formed in a dark matter halo and dark matter could still be present in the baryon-dominated environment of globular clusters. This opens the possibility of observing a dark matter self-annihilation signal. The dark matter content of the globular clusters NGC 6388 and M 15 is modelled taking into account the astrophysical processes that can be expected to influence the dark matter distribution during the evolution of the globular cluster: the adiabatic contraction of dark matter by baryons, the adiabatic growth of a black hole in the dark matter halo and the kinetic heating of dark matter by stars. 95% confidence level exclusion limits on the dark matter particle velocity-weighted annihilation cross section are derived for these dark matter haloes. In the TeV range, the limits on the velocity-weighted annihilation cross section are derived at the 10-25 cm3 s-1 level and a few 10-24 cm3 s-1 for NGC 6388 and M 15 respectively.
This article traces the interactive process between theory and research as it has been used to clarify the concept of self-care agency, a key concept in Orem's model of nursing. Theoretical ...constructions of self-care agency that have emerged in the work of Orem and the Nursing Development Conference Group are reviewed. Operational measures of self-care agency are described, particularly with regard to their underlying theoretical formulations. Factorial structures for some self-care agency instruments are related to the components of self-care agency in Orem's most recent conceptualization. Dimensions of self-care agency that are consistently supported by research studies of this phenomenon are identified.
The gamma-ray pulsar PSR B1706-44 and the adjacent supernova remnant (SNR) candidate G343.1-2.3 were observed by H.E.S.S. during a dedicated observation campaign in 2007. As a result of this ...observation campaign, a new source of very-high-energy (VHE; E > 100 GeV) gamma-ray emission, HESS J1708-443, was detected with a statistical significance of 7 sigma, although no significant point-like emission was detected at the position of the energetic pulsar itself. In this paper, the morphological and spectral analyses of the newly-discovered TeV source are presented. The centroid of HESS J1708-443 is considerably offset from the pulsar and located near the apparent center of the SNR, at RA(J2000) = 17h08m11s +/- 17s and Dec(J2000) = -44d20' +/- 4'. The source is found to be significantly more extended than the H.E.S.S. point spread function (~0.1 deg), with an intrinsic Gaussian width of 0.29 deg +/- 0.04 deg. Its integral flux between 1 and 10 TeV is ~ 3.8 x 10^-12 ph cm^-2 s^-1, equivalent to 17% of the Crab Nebula flux in the same energy range. The measured energy spectrum is well-fit by a power law with a relatively hard photon index Gamma = 2.0 +/- 0.1 (stat) +/- 0.2 (sys). Additional multi-wavelength data, including 330 MHz VLA observations, were used to investigate the VHE gamma-ray source's possible associations with the pulsar wind nebula of PSR B1706-44 and/or with the complex radio structure of the partial shell-type SNR G343.1-2.3.
Results are summarized from a 2-year study at 63 locations in the Netherlands on the effects of storm overflows from both combined and separate sewerage systems on communities of phytoplankton and ...zooplankton in the receiving waters. These organisms were suitable for determining short- and medium-term effects of pollution by urban storm-water discharges. The polluting effects were greatest in small and stagnant waters such as ponds and ditches, and in the immediate vicinity of overflows. Overflows from combined sewerage systems had a more polluting effect than those from separate sewerage systems, except for some locations in industrial areas.
The results of a 2 year study at 46 locations in the Netherlands on the long-term effects of storm overflows from both combined and separate sewerage systems on communities of sessile diatoms and ...macro-invertebrates in receiving streams, are summarized. Both types of organism showed the effects of organic pollution, but sessile diatoms were more sensitive to the pollution than macro-invertebrates which could migrate to less polluted areas. The polluting effects were greater in the immediate vicinity of an outfall, and in small ditches than in large waterbodies. Overflows from combined sewerage systems were more polluting than those from separate systems, except for those in industrial areas.
A silicon photomultiplier (SiPM) array has been developed at FBK-irst Piemonte C., Nucl. Instrum. Methods A,
568 (2006) 224; Piemonte C. et al., IEEE Trans. Nucl. Sci.,
54 (2007) 236 having 32 ...channels and a dimension of
8.0
×
1.1
mm
2
. Each 250 μm wide channel is subdivided into
5
×
22
rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved.
PDF
