147,873 research outputs found
The full squeezed CMB bispectrum from inflation
The small-scale CMB temperature we observe on the sky is modulated by
perturbations that were super-horizon at recombination, giving differential
focussing and lensing that generate a non-zero bispectrum even for single-field
inflation where local physics is identical. Understanding this signal is
important for primordial non-Gaussianity studies and also parameter constraints
from the CMB lensing bispectrum signal. Because of cancellations individual
effects can appear larger or smaller than they are in total, so a full analysis
may be required to avoid biases. I relate angular scales on the sky to physical
scales at recombination using the optical equations, and give full-sky results
for the large-scale adiabatic temperature bispectrum from Ricci focussing
(expansion of the ray bundle), Weyl lensing (convergence and shear), and
temperature redshift modulations of small-scale power. The delta N expansion of
the beam is described by the constant temperature 3-curvature, and gives a
nearly-observable version of the consistency relation prediction from
single-field inflation. I give approximate arguments to quantify the likely
importance of dynamical effects, and argue that they can be neglected for
modulation scales l <~ 100, which is sufficient for lensing studies and also
allows robust tests of local primordial non-Gaussianity using only the
large-scale modulation modes. For accurate numerical results early and
late-time ISW effects must be accounted for, though I confirm that the
late-time non-linear Rees-Sciama contribution is negligible compared to other
more important complications. The total corresponds to f_NL ~ 7 for Planck-like
temperature constraints and f_NL ~ 11 for cosmic-variance limited data to
lmax=2000. Temperature lensing bispectrum estimates are affected at the 0.2
sigma level by Ricci focussing, and up to 0.5 sigma with polarization.Comment: 12 pages, 5 figures; typos corrected, minor edit
Prospect for Charge Current Neutrino Interactions Measurements at the CERN-PS
Tensions in several phenomenological models grew with experimental results on
neutrino/antineutrino oscillations at Short-Baseline (SBL) and with the recent,
carefully recomputed, antineutrino fluxes from nuclear reactors. At a
refurbished SBL CERN-PS facility an experiment aimed to address the open issues
has been proposed [1], based on the technology of imaging in ultra-pure
cryogenic Liquid Argon (LAr). Motivated by this scenario a detailed study of
the physics case was performed. We tackled specific physics models and we
optimized the neutrino beam through a full simulation. Experimental aspects not
fully covered by the LAr detection, i.e. the measurements of the lepton charge
on event-by-event basis and their energy over a wide range, were also
investigated. Indeed the muon leptons from Charged Current (CC) (anti-)neutrino
interactions play an important role in disentangling different phenomenological
scenarios provided their charge state is determined. Also, the study of muon
appearance/disappearance can benefit of the large statistics of CC muon events
from the primary neutrino beam. Results of our study are reported in detail in
this proposal. We aim to design, construct and install two Spectrometers at
"NEAR" and "FAR" sites of the SBL CERN-PS, compatible with the already proposed
LAr detectors. Profiting of the large mass of the two Spectrometers their
stand-alone performances have also been exploited.Comment: 70 pages, 38 figures. Proposal submitted to SPS-C, CER
Focussing effects in laser-electron Thomson scattering
We study the effects of laser pulse focussing on the spectral properties of
Thomson scattered radiation. Modelling the laser as a paraxial beam we find
that, in all but the most extreme cases of focussing, the temporal envelope has
a much bigger effect on the spectrum than the focussing itself. For the case of
ultra-short pulses, where the paraxial model is no longer valid, we adopt a
sub-cycle vector beam description of the field. It is found that the emission
harmonics are blue shifted and broaden out in frequency space as the pulse
becomes shorter. Additionally the carrier envelope phase becomes important,
resulting in an angular asymmetry in the spectrum. We then use the same model
to study the effects of focussing beyond the limit where the paraxial expansion
is valid. It is found that fields focussed to sub-wavelength spot sizes produce
spectra that are qualitatively similar to those from sub-cycle pulses due to
the shortening of the pulse with focussing. Finally, we study high-intensity
fields and find that, in general, the focussing makes negligible difference to
the spectra in the regime of radiation reaction.Comment: 14 pages, 17 figure
Stark deceleration of CaF molecules in strong- and weak-field seeking states
We report the Stark deceleration of CaF molecules in the strong-field seeking
ground state and in a weak-field seeking component of a rotationally-excited
state. We use two types of decelerator, a conventional Stark decelerator for
the weak-field seekers, and an alternating gradient decelerator for the
strong-field seekers, and we compare their relative merits. We also consider
the application of laser cooling to increase the phase-space density of
decelerated molecules.Comment: 10 pages, 8 figure
MONTE CARLO SIMULATIONS OF MUON PRODUCTION
Muon production requirements for a muon collider are presented. Production of
muons from pion decay is studied. Lithium lenses and solenoids are considered
for focussing pions from a target, and for matching the pions into a decay
channel. Pion decay channels of alternating quadrupoles and long solenoids are
compared. Monte Carlo simulations are presented for production of by protons over a wide energy range, and criteria for
choosing the best proton energy are discussed.Comment: Latex uses mu95.sty, 19 pages, 5 postscript figures. A postscript
file can be seen at URL http://www.cap.bnl.gov/~cap/mumu/important.html
Search for Publication
Moving from rabies research to rabies control: lessons from India
BACKGROUND:
Despite the availability of effective interventions and public recognition of the severity of the problem, rabies continues to suffer neglect by programme planners in India and other low and middle income countries. We investigate whether this state of 'policy impasse' is due to, at least in part, the research community not catering to the information needs of the policy makers.
METHODS & FINDINGS:
Our objective was to review the research output on rabies from India and examine its alignment with national policy priorities. A systematic literature review of all rabies research articles published from India between 2001 and 2011 was conducted. The distribution of conducted research was compared to the findings of an earlier research prioritization exercise. It was found that a total of 93 research articles were published from India since 2001, out of which 61% consisted of laboratory based studies focussing on rabies virus. Animals were the least studied group, comprising only 8% of the research output. One third of the articles were published in three journals focussing on vaccines and infectious disease epidemiology and the top 4 institutions (2 each from the animal and human health sectors) collectively produced 49% of the national research output. Biomedical research related to development of new interventions dominated the total output as opposed to the identified priority domains of socio-politic-economic research, basic epidemiological research and research to improve existing interventions.
CONCLUSION:
The paper highlights the gaps between rabies research and policy needs, and makes the case for developing a strategic research agenda that focusses on rabies control as an expected outcome
Organic Farming for a New Millennium - status and future challenges
The proceedings contains abstracts of all papers and posters presented at the seminar. A few papers that arrived later were published in an attachment. See attached documents
Uniformity transition for ray intensities in random media
This paper analyses a model for the intensity of distribution for rays propagating without absorption in a random medium. The random medium is modelled as a dynamical map. After N iterations, the intensity is modelled as a sum S of N contributions from different trajectories, each of which is a product of N independent identically distributed random variables xk, representing successive focussing or de-focussing events. The number of ray trajectories reaching a given point is assumed to proliferate exponentially: N=ΛN, for some Λ>1. We investigate the probability distribution of S. We find a phase transition as parameters of the model are varied. There is a phase where the fluctuations of S are suppressed as N → ∞, and a phase where the S has large fluctuations, for which we provide a large deviation analysis
Parenting interventions for male young offenders: a review of the evidence on what works
Approximately one in four incarcerated male young offenders in the UK is an actual or expectant father. This paper reviews evidence on the effectiveness of parenting interventions for male young offenders. We conducted systematic searches across 20 databases and consulted experts. Twelve relevant evaluations were identified: 10 from the UK, of programmes for incarcerated young offenders, and two from the US, of programmes for young parolees. None used experimental methods or included a comparison group. They suggest that participants like the courses, find them useful, and the interventions may improve knowledge about, and attitudes to, parenting. Future interventions should incorporate elements of promising parenting interventions with young fathers in the community, for example, and/or with older incarcerated parents. Young offender fathers have specific developmental, rehabilitative, and contextual needs. Future evaluations should collect longer-term behavioural parent and child outcome data and should use comparison groups and, ideally, randomization
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