Direct Dark Matter Detection with Velocity Distribution in the Eddington approach

Exotic dark matter together with the vacuum energy (associated with the cosmological constant) seem to dominate the Universe. Thus its direct detection is central to particle physics and cosmology. Supersymmetry provides a natural dark matter candidate, the lightest supersymmetric particle (LSP). One essential ingredient in obtaining the direct detection rates is the density and the velocity distribution of the LSP in our vicinity. In the present paper we study simultaneously density profiles and velocity distributions in the context of the Eddington approach. In such an approach, unlike the commonly assumed Maxwell-Boltzmann (M-B) distribution, the upper bound of the velocity arises naturally from the potential.Comment: 21 LaTex pages, 27 figure

Germination responses of a dry sclerophyll forest soil-stored seedbank to fire related cues

Fire is an integral component of many ecosystems worldwide. Many plant species require fire-related cues, primarily heat and smoke, to trigger germination. Despite the importance of this process, the responses of many Australian species to these cues are unknown. Without this knowledge fire management strategies may be developed that are inappropriate for individual species and vegetation communities. In this study we examined the responses of a dry sclerophyll forest seed bank to heat and smoke germination cues. Analysis was possible for 48 taxa within the soil seedbank with 34 of these showing a response to one or both of the germination cues. 10 species responded to the heat treatment, 11 species responded to the smoke treatment and 13 species responded to both the heat and smoke treatments. Germination cues acted independently for all species considered. Results in this study were consistent with published reports for most species, although some differences were seen at the species and genus level. The study highlights the importance of fire-related cues in enhancing germination of a large proportion of the species occurring in dry sclerophyll forests

A Field Effect Transitor based on the Mott Transition in a Molecular Layer

Here we propose and analyze the behavior of a FET--like switching device, the Mott transition field effect transistor, operating on a novel principle, the Mott metal--insulator transition. The device has FET-like characteristics with a low ``ON'' impedance and high ``OFF'' impedance. Function of the device is feasible down to nanoscale dimensions. Implementation with a class of organic charge transfer complexes is proposed.Comment: Revtex 11pages, Figures available upon reques

Contract, The Caney Lodge No. 324, A.F. and A.M., 1896

A contract for the Caney Lodge No. 324, A.F. and A.M. Building Association to construct a second story at lot 27 of block 54 in Caney, Kansas

Long-Term Evolution of Massive Black Hole Binaries. II. Binary Evolution in Low-Density Galaxies

We use direct-summation N-body integrations to follow the evolution of binary black holes at the centers of galaxy models with large, constant-density cores. Particle numbers as large as 400K are considered. The results are compared with the predictions of loss-cone theory, under the assumption that the supply of stars to the binary is limited by the rate at which they can be scattered into the binary's influence sphere by gravitational encounters. The agreement between theory and simulation is quite good; in particular, we are able to quantitatively explain the observed dependence of binary hardening rate on N. We do not verify the recent claim of Chatterjee, Hernquist & Loeb (2003) that the hardening rate of the binary stabilizes when N exceeds a particular value, or that Brownian wandering of the binary has a significant effect on its evolution. When scaled to real galaxies, our results suggest that massive black hole binaries in gas-poor nuclei would be unlikely to reach gravitational-wave coalescence in a Hubble time.Comment: 13 pages, 8 figure

The Sexual health of pupils in years 4 to 6 of primary schools in rural Tanzania

Background/objectives: There is an urgent need for effective interventions to improve the sexual and\ud reproductive health of adolescents. Reliable data on the sexual health of adolescents are needed to guide\ud the development of such interventions. The aim was to describe the sexual health of pupils in years 4 to 6 of\ud 121 rural primary schools in north western Tanzania, before the implementation of an innovative sexual\ud health intervention in 58 of the schools.\ud Methods: A cross sectional survey of primary school pupils in rural Tanzania was carried out. The study\ud population comprised pupils registered in years 4 to 6 of 121 primary schools in 20 rural communities in\ud 1998. Basic demographic information was collected from all pupils seen. Those born before 1 January\ud 1985 (aged approximately 14 years and over) were invited to participate in the survey, and asked about\ud their knowledge and attitudes towards sexual health issues, and their sexual experience. A urine specimen\ud was requested and tested for HIV, Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and, for\ud females, pregnancy.\ud Results: 9283 pupils born before 1 January 1985 were enrolled and provided demographic information\ud and a urine sample. Male pupils were significantly older than females (mean age 15.5 years v 14.8 years,\ud p,0.001), but all other demographic characteristics were similar between the sexes. 14 (0.2%) of the\ud enrolled pupils (four male and 10 female) were HIV positive, 83 (0.9%) were positive for CT, and 12\ud (0.1%) for NG. 32 female pupils (0.8%) were positive by pregnancy test. Sexual experience was reported\ud by one fifth of primary school girls, and by almost half of boys. Only 45/114 (39%) girls with biological\ud markers of sexual activity reported having had sex.\ud Conclusions: HIV, CT, NG, and pregnancy were present though at relatively low levels among pupils in\ud years 4 to 6 of primary school. A high proportion of pupils with a biological marker of sexual activity\ud denied ever having had sex. Alternative ways of collecting sensitive data about the sexual behaviour of\ud school pupils should be explored

Collisional dynamics around binary black holes in galactic centers

We follow the sinking of two massive black holes in a spherical stellar system where the black holes become bound under the influence of dynamical friction. Once bound, the binary hardens by three-body encounters with surrounding stars. We find that the binary wanders inside the core, providing an enhanced supply of reaction partners for the hardening. The binary evolves into a highly eccentric orbit leading to coalescence well beyond a Hubble time. These are the first results from a hybrid ``self consistent field'' (SCF) and direct Aarseth N-body integrator (NBODY6), which combines the advantages of the direct force calculation with the efficiency of the field method. The code is designed for use on parallel architectures and is therefore applicable to collisional N-body integrations with extraordinarily large particle numbers (> 10^5). This creates the possibility of simulating the dynamics of both globular clusters with realistic collisional relaxation and stellar systems surrounding supermassive black holes in galactic nuclei.Comment: 38 pages, 13 figures, submitted to ApJ, accepted, revised text and added figure

The possible origin of the faint fuzzy star clusters in NGC 1023

In the lenticular galaxy NGC 1023 a new population of star clusters (``faint fuzzies'') was recently discovered by Larsen & Brodie. These clusters are found inside the disc and are faint (23 < V < 24 mag) and extended with effective radii of r_eff approx. 7 to 15 pc. We present here N-body calculations of a likely formation-scenario through merging star clusters in clusters of star clusters (super-clusters). Such super-clusters are observed to form in interacting galaxies. The resulting merger objects have masses comparable to the ``faint fuzzies'' and show large effective radii (r_eff > 7 pc). Even though these objects are suffering from strong tidal forces they are able to survive and reach the estimated ages of the extended star clusters in NGC 1023.Comment: 19 pages, 12 figures, accepted by A

Combined thermal and FTIR analysis of porous silicon based nano-energetic films

Nanoporous silicon (pSi) films on a silicon wafer were loaded with sodium perchlorate (SP) and perfluoropolyether (PFPE) oxidising agents to generate a pyrotechnic energetic material. The potentially violent reaction between the silicon and the loaded oxidising agent was studied using correlated differential scanning calorimetry (DSC) and FTIR spectroscopy for samples heated continuously between ambient and 500 degrees C. We observed that the energetic reaction between pSi and SP depended on the presence of various hydride species on the surface of freshly etched pSi, and on formation of volatile free radical species released during either oxidation of the surface in the presence of air at about 200 degrees C or during desorption of the hydride above 270 degrees C in the absence of oxygen. However, energetic reactions between pSi and PFPE were delayed until pyrolysis of the PFPE above 390 degrees C in the absence of oxygen, suggesting PFPE's suitability for pyrotechnics applications. Correlated thermal and spectroscopic methods of analysis gave new insights into the earliest stages of the reaction of these energetic materials