Program for computing partial pressures from residual gas analyzer data

A computer program for determining the partial pressures of various gases from residual-gas-analyzer data is given. The analysis of the ion currents of 18 m/e spectrometer peaks allows the determination of 12 gases simultaneously. Comparison is made to ion-gage readings along with certain other control information. The output data are presented in both tabular and graphical form

Extreme alpha-clustering in the 18O nucleus

The structure of the 18O nucleus at excitation energies above the alpha decay threshold was studied using 14C+alpha resonance elastic scattering. A number of states with large alpha reduced widths have been observed, indicating that the alpha-cluster degree of freedom plays an important role in this N not equal Z nucleus. However, the alpha-cluster structure of this nucleus is very different from the relatively simple pattern of strong alpha-cluster quasi-rotational bands in the neighboring 16O and 20Ne nuclei. A 0+ state with an alpha reduced width exceeding the single particle limit was identified at an excitation energy of 9.9+/-0.3 MeV. We discuss evidence that states of this kind are common in light nuclei and give possible explanations of this feature.Comment: 4 pages, 2 figures, 1 table. Resubmission with minor changes for clarity, including removal of one figur

Rest-frame properties of 32 gamma-ray bursts observed by the Fermi Gamma-Ray Burst Monitor

Aims: In this paper we study the main spectral and temporal properties of gamma-ray bursts (GRBs) observed by Fermi/GBM. We investigate these key properties of GRBs in the rest-frame of the progenitor and test for possible intra-parameter correlations to better understand the intrinsic nature of these events. Methods: Our sample comprises 32 GRBs with measured redshift that were observed by GBM until August 2010. 28 of them belong to the long-duration population and 4 events were classified as short/hard bursts. For all of these events we derive, where possible, the intrinsic peak energy in the $\nu F_{\nu}$ spectrum (\eprest), the duration in the rest-frame, defined as the time in which 90% of the burst fluence was observed (\tninetyrest) and the isotropic equivalent bolometric energy (\eiso). Results: The distribution of \eprest has mean and median values of 1.1 MeV and 750 keV, respectively. A log-normal fit to the sample of long bursts peaks at ~800 keV. No high-\ep population is found but the distribution is biased against low \ep values. We find the lowest possible \ep that GBM can recover to be ~ 15 keV. The \tninetyrest distribution of long GRBs peaks at ~10 s. The distribution of \eiso has mean and median values of $8.9\times 10^{52}$ erg and $8.2 \times 10^{52}$ erg, respectively. We confirm the tight correlation between \eprest and \eiso (Amati relation) and the one between \eprest and the 1-s peak luminosity ($L_p$) (Yonetoku relation). Additionally, we observe a parameter reconstruction effect, i.e. the low-energy power law index $\alpha$ gets softer when \ep is located at the lower end of the detector energy range. Moreover, we do not find any significant cosmic evolution of neither \eprest nor \tninetyrest.Comment: accepted by A&

The first observed stellar occultations by the irregular satellite Phoebe (Saturn IX) and improved rotational period

peer reviewedWe report six stellar occultations by Phoebe (Saturn IX), an irregular satellite of Saturn, obtained between mid-2017 and mid-2019. The 2017 July 6 event was the first stellar occultation by an irregular satellite ever observed. The occultation chords were compared to a 3D shape model of the satellite obtained from Cassini observations. The rotation period available in the literature led to a sub-observer point at the moment of the observed occultations where the chords could not fit the 3D model. A procedure was developed to identify the correct sub-observer longitude. It allowed us to obtain the rotation period with improved precision compared to the currently known value from literature. We show that the difference between the observed and the predicted sub-observer longitude suggests two possible solutions for the rotation period. By comparing these values with recently observed rotational light curves and single- chord stellar occultations, we can identify the best solution for Phoebe's rotational period as 9.27365 ± 0.00002 h. From the stellar occultations, we also obtained six geocentric astrometric positions in the ICRS as realized by the Gaia DR2 with uncertainties at the 1-mas level

Ceratoscopelus maderensis : pecular sound-scattering layer identified with this myctophid fish

Reprint. Science, vol. 160, no. 3831, 1968, pp. 991-993. Originally issued as Reference No. 68-58, series later renamed WHOI-.A sound- scattering layer, composed of discrete hyperbolic echo-sequences and apparently restricted to the Slope Water region of the western North Atlantic, has been identified from the Deep Submergence Research Vehicle ALVIN with schools of the myctophid fish Ceratoscopelus maderensis. By diving into the layer and using ALVIN's echo-ranging sonar, we approached and visually identified the sound scatterers. The number of echo sequences observed with the surface echo-sounder (1 /23. 76 x 105 cubic meters of water) checked roughly with the number of sonar targets observed from the submarine (1/7. 45 x 105 cubic meters) . The fish schools appeared to be 5 to 10 meters thick, 10 to 100 meters in diameter, and on centers 100 to 200 meters apart. Density within schools was estimated at 10 to 15 fish per cubic meter.Supported in part by contracts Nonr-3484(00) and Nonr-4029(00) and by NSF grant GB-4431

Quantum Newtonian Dynamics on a Light Front

We recall the special features of quantum dynamics on a light-front (in an infinite momentum frame) in string and field theory. The reason this approach is more effective for string than for fields is stressed: the light-front dynamics for string is that of a true Newtonian many particle system, since a string bit has a fixed Newtonian mass. In contrast, each particle of a field theory has a variable Newtonian mass P^+, so the Newtonian analogy actually requires an infinite number of species of elementary Newtonian particles. This complication substantially weakens the value of the Newtonian analogy in applying light-front dynamics to nonperturbative problems. Motivated by the fact that conventional field theories can be obtained as infinite tension limits of string theories, we propose a way to recast field theory as a standard Newtonian system. We devise and analyze some simple quantum mechanical systems that display the essence of the proposal, and we discuss prospects for applying these ideas to large N_c QCD.Comment: 13 pages, 3 figures, LaTex, psfig, references added, APS copyrigh

Calculating the Rest Tension for a Polymer of String Bits

We explore the application of approximation schemes from many body physics, including the Hartree-Fock method and random phase approximation (RPA), to the problem of analyzing the low energy excitations of a polymer chain made up of bosonic string bits. We accordingly obtain an expression for the rest tension $T_0$ of the bosonic relativistic string in terms of the parameters characterizing the microscopic string bit dynamics. We first derive an exact connection between the string tension and a certain correlation function of the many-body string bit system. This connection is made for an arbitrary interaction potential between string bits and relies on an exact dipole sum rule. We then review an earlier calculation by Goldstone of the low energy excitations of a polymer chain using RPA. We assess the accuracy of the RPA by calculating the first order corrections. For this purpose we specialize to the unique scale invariant potential, namely an attractive delta function potential in two (transverse) dimensions. We find that the corrections are large, and discuss a method for summing the large terms. The corrections to this improved RPA are roughly 15\%.Comment: 44 pages, phyzzx, psfig required, Univ. of Florida preprint, UFIFT-HEP-94

The writing on the wall: the concealed communities of the East Yorkshire horselads

This paper examines the graffiti found within late nineteenth and early-twentieth century farm buildings in the Wolds of East Yorkshire. It suggests that the graffiti were created by a group of young men at the bottom of the social hierarchy - the horselads – and was one of the ways in which they constructed a distinctive sense of communal identity, at a particular stage in their lives. Whilst it tells us much about changing agricultural regimes and social structures, it also informs us about experiences and attitudes often hidden from official histories and biographies. In this way, the graffiti are argued to inform our understanding, not only of a concealed community, but also about their hidden histor