1,354 research outputs found
Conversion of neutron stars to strange stars as the central engine of gamma-ray bursts
We study the conversion of a neutron star to a strange star as a possible
energy source for gamma-ray bursts. We use different recent models for the
equation of state of neutron star matter and strange quark matter. We show that
the total amount of energy liberated in the conversion is in the range of (1-4)
10^{53} ergs (one order of magnitude larger than previous estimates) and is in
agreement with the energy required to power gamma-ray burst sources at
cosmological distances.Comment: ApJ, 530, 2000 February 20, Lxxx (in press
Studi Deformasi Waduk Pendidikan Diponegoro Tahun 2016
According to SNI No. 1731-1989 dam is any artificial barrier, urugan type or any other type that can hold or store water both natural and artificial. In addition to benefits are very much dams also have a high risk because has the potential danger of collapse that could result in the loss of life and material losses, therefore it needs to be observed deformation to determine the condition of the dam.In this research will be observation of the deformation of Pendidikan Diponegoro dam, with GPS (Global Positioning System) observation methods will be observed of 9 monitoring points deformation (bench mark) spread around the body of the dam, the GPS observed data will be processing using scientific software GAMIT 10.6, deformation monitoring points were also observed changes in distance and height from the control points are placed outside the body of the dam, deformation observations carried out from April to June 2016, with twice the period of observation.The results of GPS observations during the observation period showed deformation monitoring points change the coordinate value with ranging from 0.06 cm to 1.4 cm for the X axis, 0.03 cm to 1.9 cm for the Y axis, and 0.4 cm to 1.3 cm for the Z axis. Distance and height changes based on total station and waterpass measurement during the observation period ranging from 0.09 mm to 1.7 mm and 0.15 mm to 1.8 mm. From the result of the dam deformation observation by GPS observation methods, total station, and waterpass shows deformation of the deformation monitoring points during the observation period, but based on the statistical test with 95% confidence level showed that there is no deformation of all the deformation monitoring points
Single production of vector-like bottom quark at the LHeC
Existences of vector-like quarks (VLQs) are predicted in many new physics
scenarios beyond the Standard Model (SM). We study the possibility of detecting
the vector-like bottom quark (VLQ-) being the singlet with electric
charge at the Large Hadron Electron Collider (LHeC) in a
model-independent framework. The decay properties and single production of
VLQ- at the LHeC are explored. Three types of signatures are investigated.
By carrying out a fast simulation for the signals and the corresponding
backgrounds, the signal significances are obtained. Our numerical results show
that detecting of VLQ- via the semileptonic channel is better than via the
fully hadronic or leptonic channel.Comment: 21 pages, 10 figures, Prepared for publicatio
Quark matter in compact stars: astrophysical implications and possible signatures
After a brief non technical introduction of the basic properties of strange
quark matter (SQM) in compact stars, we consider some of the late important
advances in the field, and discuss some recent astrophysical observational data
that could shed new light on the possible presence of SQM in compact stars. We
show that above a threshold value of the gravitational mass a neutron star
(pure hadronic star) is metastable to the decay (conversion) to an hybrid
neutron star or to a strange star. We explore the consequences of the
metastability of "massive" neutron stars and of the existence of stable compact
"quark" stars (hybrid neutron stars or strange stars) on the concept of
limiting mass of compact stars, and we give an extension of this concept with
respect to the "classical" one given in 1939 by Oppenheimer and Volkoff.Comment: Invited talk at "the Eleventh Marcel Grossman Meeting on General
Relativity", Berlin 200
Imaging in myeloma with focus on advanced imaging techniques.
In recent years, there have been major advances in the imaging of myeloma with whole body MRI incorporating diffusion-weighted imaging, emerging as the most sensitive modality. Imaging is now a key component in the work-up of patients with a suspected diagnosis of myeloma. The International Myeloma Working Group now specifies that more than one focal lesion on MRI or lytic lesion on whole body low-dose CT or fludeoxyglucose (FDG) PET/CT fulfil the criteria for bone damage requiring therapy. The recent National Institute for Health and Care Excellence myeloma guidelines recommend imaging in all patients with suspected myeloma. In addition, there is emerging data supporting the use of functional imaging techniques (WB-DW MRI and FDG PET/CT) to predict outcome and evaluate response to therapy. This review summarises the imaging modalities used in myeloma, the latest guidelines relevant to imaging and future directions
The {\tt Mathematica} package {\tt TopoID} and its application to the Higgs boson production cross section
We present the {\tt Mathematica} package {\tt TopoID} which aims at the
automation of several steps in multiloop calculations. The algorithm which lies
at the very core of the package is described and illustrated with an example.
The main features of {\tt TopoID} are stated and some of them are briefly
demonstrated for NLO or NNLO Higgs boson production.Comment: 5 pages, 1 figure, contribution to the proceedings of ACAT, 18 - 22
January 2016, UTFSM, Valparaiso, Chile v2: updated references, added preprint
number DESY 16-03
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