9,244 research outputs found
Self-Maintained Coherent Oscillations in Dense Neutrino Gases
We present analytical solutions to the nonlinear equations describing the
behavior of a gas of neutrinos with two flavors. Self-maintained coherent
flavor oscillations are shown to occur when the gas density exceeds a critical
value determined by the neutrino masses and the mean neutrino energy in the
gas. Similar oscillations may have occurred in the early Universe.Comment: To appear in Physical Review D, July 199
Training of fisheries operatives personnel in India
The growth and development of any industry is dependent on the availability of trained tech nical skill. In the case of the fishing industry the technical skill is
represented in the two broad categories of personnel viz. the operative personel who are engaged in the process of catching fish and the supporting shore
technicians who cater to the needs of the former by way of looking after the supply, maintenance and repair work of the necessa ry craft and gear and also
the distribution of catches through appropriate channels
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A comparison of stage-specific all-cause mortality between testicular sex cord stromal tumors and germ cell tumors: results from the National Cancer Database.
BackgroundTesticular sex cord stromal tumors (SCSTs) are managed similarly to germ cell tumors (GCTs); however, few studies have directly compared outcomes between these tumor types. Using the National Cancer Database (NCDB), we sought to compare overall and stage-specific all-cause mortality (ACM) between SCSTs versus GCTs.MethodsNCDB was queried for patients diagnosed with SCSTs and GCTs between 2004 and 2013. Descriptive statistics were used to compare sociodemographic and clinical characteristics between groups. Univariable and multivariable Cox proportional hazards regression analyses were used to assess associations with ACM.ResultsWe identified 42,192 patients diagnosed with testicular cancer between 2004 and 2013, with 280 having SCSTs and 41,912 patients having GCTs. Median age for SCSTs and GCTs was 45 (interquartile range [IQR] 34-59) and 34 (IQR 27-43), respectively (p < 0.001). Median follow-up was 39 and 52 months, respectively. Overall, patients with SCSTs had greater risk of ACM compared to those with GCTs (HR 1.69, 95% CI 1.14-2.50). Private insurance, greater education, and fewer comorbidities were associated with reduced risk of ACM (p < 0.05 for all). Among those with stage I disease, tumor type was not associated with ACM on multivariable analysis. Among those with stage II/III disease, patients with SCSTs had increased risk of ACM compared to patients with GCTs (HR 3.29, 95% CI 1.89-5.72).ConclusionsPatients with advanced SCSTs had worse survival outcomes compared to those with advanced GCTs. These data suggest a need for further investigation to ascertain effective management recommendations for SCSTs
Multi-Dimensional Hermite Polynomials in Quantum Optics
We study a class of optical circuits with vacuum input states consisting of
Gaussian sources without coherent displacements such as down-converters and
squeezers, together with detectors and passive interferometry (beam-splitters,
polarisation rotations, phase-shifters etc.). We show that the outgoing state
leaving the optical circuit can be expressed in terms of so-called
multi-dimensional Hermite polynomials and give their recursion and
orthogonality relations. We show how quantum teleportation of photon
polarisation can be modelled using this description.Comment: 10 pages, submitted to J. Phys. A, removed spurious fil
Descent Relations and Oscillator Level Truncation Method
We reexamine the oscillator level truncation method in the bosonic String
Field Theory (SFT) by calculation the descent relation =Z_3<V_2|. For
the ghost sector we use the fermionic vertices in the standard oscillator
basis. We propose two new schemes for calculations. In the first one we assume
that the insertion satisfies the overlap equation for the vertices and in the
second one we use the direct calculations. In both schemes we get the correct
structures of the exponent and pre-exponent of the vertex <V_2|, but we find
out different normalization factors Z_3.Comment: 21 pages, 10 figures, Late
The Geometric Phase and Ray Space Isometries
We study the behaviour of the geometric phase under isometries of the ray
space. This leads to a better understanding of a theorem first proved by
Wigner: isometries of the ray space can always be realised as projections of
unitary or anti-unitary transformations on the Hilbert space. We suggest that
the construction involved in Wigner's proof is best viewed as an use of the
Pancharatnam connection to ``lift'' a ray space isometry to the Hilbert space.Comment: 17 pages, Latex file, no figures, To appear in Pramana J. Phy
Neutrino Oscillations in the Early Universe with Nonequilibrium Neutrino Distributions
Around one second after the big bang, neutrino decoupling and -
annihilation distort the Fermi-Dirac spectrum of neutrino energies. Assuming
neutrinos have masses and can mix, we compute the distortions using
nonequilibrium thermodynamics and the Boltzmann equation. The flavor behavior
of neutrinos is studied during and following the generation of the distortion.Comment: accepted for publication in Physical Review
Splee:A declarative information-based language for multiagent interaction protocols
The Blindingly Simple Protocol Language (BSPL) is a novel information-based approach for specifying interaction protocols that can be enacted by agents in a fully decentralized manner via asynchronous messaging. We introduce Splee, an extension of BSPL. The extensions fall into two broad categories: multicast and roles. In Splee, a role binding is information that is dynamically generated during protocol enactment, potentially as the content (payload) of communication between two agents. Multicast communication is the idea that a message is sent to a set of agents. The two categories of extensions are interconnected via novel features such as set roles (the idea that a role binding can be a set of agents) and subroles (the idea that agents playing a role must be a subset of agents playing another role). We give the formal semantics of Splee and give small model characterizations of the safety and liveness of Splee protocols. We also introduce the pragmatic idea of query attachments for messages. Query attachments take advantage of Splee's information-orientation, and can help restrict the information (parameter bindings) communicated in a message
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