Very high energy gamma rays from the Crab Nebula

Observations of the Crab pulsar using the atmospheric Cerenkov technique were conducted for 22 hours. The light curve obtained shows a single peak at approximately the position of the expected main peak with a significance level of 3.2 sigma. The pulsed flux above 200 GeV is 2.5 + or - 0.8 x 10 to the 11th power cm(-2)s(-1)

Galactic distribution of interstellar Al-26

A narrow cosmic gamma ray line at 1809 keV was discovered which was interpreted as resulting from the decay of approximately 3 M sub theta of Al-26 residing in the galactic disk. While its intrinsic width was unresolved by the HEAO 3 spectrometer, a (1 sigma) limit of 3 keV FWHM was obtained; this corresponds to bulk motions of v 250 km/s, which is consistent with material at rest in the ISM. Sites which have been suggested include type II supernovae and massive stars which are members of the extreme population I, as well as novae and red giants which are associated with an older disk population. The HEAO 3 data was used to distinguish between these two stellar populations

Gamma-ray burst variability above 4 MeV

The relationship between the hard X-ray and gamma ray emissions during four bursts using the anti-coincidence shields of the High Energy Astronomy Observatory 3 (HEAO 3) Gamma Ray Spectrometer is explored. Recent observations of gamma ray bursts by the Solar Maximum Mission Gamma Ray Spectrometer (GRS) have shown that high energy emission above 1 MeV is a common and energetically important feature (Matz et al. 1985). Time histories of four gamma ray bursts in 3 energy bands ( keV, around 511 keV, and 4 MeV) with 10.24 a resolution show that the 4 MeV flux is only weakly coupled to the spectrum below approximately 600 keV

Monitoring the Low-Energy Gamma-Ray Sky Using Earth Occultation with GLAST GBM

Long term all-sky monitoring of the 20 keV – 2 MeV gamma-ray sky using the Earth occultation technique was demonstrated by the BATSE instrument on the Compton Gamma Ray Observatory. The principles and techniques used for the development of an end-to-end earth occultation data analysis system for BATSE can be extended to the GLAST Burst Monitor (GBM), resulting in multiband light curves and time-resolved spectra in the energy range 8 keV to above 1 MeV for known gamma-ray sources and transient outbursts, as well as the discovery of new sources of gamma-ray emission. In this paper we describe the application of the technique to the GBM. We also present the expected sensitivity for the GBM

Questioning policy, youth participation and lifestyle sports

Young people have been identified as a key target group for whom participation in sport and physical activity could have important benefits to health and wellbeing and consequently have been the focus of several government policies to increase participation in the UK. Lifestyle sports represent one such strategy for encouraging and sustaining new engagements in sport and physical activity in youth groups, however, there is at present a lack of understanding of the use of these activities within policy contexts. This paper presents findings from a government initiative which sought to increase participation in sport for young people through provision of facilities for mountain biking in a forest in south-east England. Findings from qualitative research with 40 young people who participated in mountain biking at the case study location highlight the importance of non-traditional sports as a means to experience the natural environments through forms of consumption which are healthy, active and appeal to their identities. In addition, however, the paper raises questions over the accessibility of schemes for some individuals and social groups, and the ability to incorporate sports which are inherently participant-led into state-managed schemes. Lifestyle sports such as mountain biking involve distinct forms of participation which present a challenge for policy-makers who seek to create and maintain sustainable communities of youth participants

BATSE Soft Gamma-Ray Observations of GROJ0422+32

We report results of a comprehensive study of the soft gamma-ray (30 keV to 1.7 MeV) emission of GROJ0422+32 during its first known outburst in 1992. These results were derived from the BATSE earth-occultation database with the JPL data analysis package, EBOP (Enhanced BATSE Occultation Package). Results presented here focus primarily on the long-term temporal and spectral variability of the source emission associated with the outburst. The light curves with 1-day resolution in six broad energy-bands show the high-energy flux (>200 keV) led the low-energy flux (<200 keV) by ~5 days in reaching the primary peak, but lagged the latter by ~7 days in starting the declining phase. We confirm the "secondary maximum" of the low-energy (<200 keV) flux at TJD 8970-8981, ~120 days after the first maximum. Our data show that the "secondary maximum" was also prominent in the 200-300 keV band, but became less pronounced at higher energies. During this 200-day period, the spectrum evolved from a power-law with photon index of 1.75 on TJD 8839, to a shape that can be described by a Comptonized model or an exponential power law below 300 keV, with a variable power-law tail above 300 keV. The spectrum remained roughly in this two-component shape until ~9 November (TJD 8935) and then returned to the initial power-law shape with an index of ~2 until the end of the period. The correlation of the two spectral shapes with the high and low luminosities of the soft gamma-ray emission is strongly reminiscent of that seen in Cygnus X-1. We interpret these results in terms of the Advection Dominated Accretion Flow (ADAF) model with possibly a "jet-like" region that persistently produced the non-thermal power-law gamma rays observed throughout the event.Comment: 40 pages total, including 10 figures and 2 table

Dedicated transcriptomics combined with power analysis lead to functional understanding of genes with weak phenotypic changes in knockout lines

Author summary Knockout mice benefit the understanding of gene functions in mammals. However, it has proven difficult for many genes to identify clear phenotypes, related due to lack of sufficient assays. As Lewis Wolpert put it in a famous quote “But did you take them to the opera?”, thus metaphorically alluding to the need to extend phenotyping efforts. This insight led to the establishment of phenotyping pipelines that are nowadays routinely used to characterize knock-out lines. However, transcriptomic approaches based on RNA-Seq have been much less explored for such deep-level studies. We conducted here both, a theoretical power analysis and practical RNA-Seq experiments on two knockout lines with small phenotypic effects to investigate the parameters including sample size, sequencing depth, fold change, and dispersion. Our dedicated RNA-Seq studies discovered thousands of genes with small transcriptional changes and enriched in specific functions in both knockout lines. We find that it is more important to increase the number of samples than to increase the sequencing depth. Our work shows that a deep RNA-Seq study on knockouts is powerful for understanding gene functions in cases of weak phenotypic effects, and provides a guideline for the experimental design of such studies

Bubble burst as jamming phase transition

Recently research on bubble and its burst attract much interest of researchers in various field such as economics and physics. Economists have been regarding bubble as a disorder in prices. However, this research strategy has overlooked an importance of the volume of transactions. In this paper, we have proposed a bubble burst model by focusing the transactions incorporating a traffic model that represents spontaneous traffic jam. We find that the phenomenon of bubble burst shares many similar properties with traffic jam formation by comparing data taken from US housing market. Our result suggests that the transaction could be a driving force of bursting phenomenon.Comment: 9 pages,12 figure