1,503 research outputs found
Near-Infrared Super Resolution Imaging with Metallic Nanoshell Particle Chain Array
We propose a near-infrared super resolution imaging system without a lens or
a mirror but with an array of metallic nanoshell particle chain. The imaging
array can plasmonically transfer the near-field components of dipole sources in
the incoherent and coherent manners and the super resolution images can be
reconstructed in the output plane. By tunning the parameters of the metallic
nanoshell particle, the plasmon resonance band of the isolate nanoshell
particle red-shifts to the near-infrared region. The near-infrared super
resolution images are obtained subsequently. We calculate the field intensity
distribution at the different planes of imaging process using the finite
element method and find that the array has super resolution imaging capability
at near-infrared wavelengths. We also show that the image formation highly
depends on the coherence of the dipole sources and the image-array distance.Comment: 15 pages, 6 figure
Exploring novel correlations in trilepton channels at the LHC for the minimal supersymmetric inverse seesaw model
We investigate signatures of the minimal supersymmetric inverse seesaw model
at the large hadron collider (LHC) with three isolated leptons and large
missing energy (3\ell + \mET or 2\ell + 1\tau + \mET, with \ell=e,\mu) in the
final state. This signal has its origin in the decay of chargino-neutralino
(\chpm1\ntrl2) pair, produced in pp collisions. The two body decays of the
lighter chargino into a charged lepton and a singlet sneutrino has a
characteristic decay pattern which is correlated with the observed large
atmospheric neutrino mixing angle. This correlation is potentially observable
at the LHC by looking at the ratios of cross sections of the trilepton + \mET
channels in certain flavour specific modes. We show that even after considering
possible leading standard model backgrounds these final states can lead to
reasonable discovery significance at the LHC with both 7 TeV and 14 TeV
center-of-mass energy.Comment: 28 pages, 9 .eps figures. 3 new figures and discussions on LHC
observables added, minor modifications in text and in the abstract, 23 new
references added, matches with the published version in JHE
A reverse engineering approach to the suppression of citation biases reveals universal properties of citation distributions
The large amount of information contained in bibliographic databases has
recently boosted the use of citations, and other indicators based on citation
numbers, as tools for the quantitative assessment of scientific research.
Citations counts are often interpreted as proxies for the scientific influence
of papers, journals, scholars, and institutions. However, a rigorous and
scientifically grounded methodology for a correct use of citation counts is
still missing. In particular, cross-disciplinary comparisons in terms of raw
citation counts systematically favors scientific disciplines with higher
citation and publication rates. Here we perform an exhaustive study of the
citation patterns of millions of papers, and derive a simple transformation of
citation counts able to suppress the disproportionate citation counts among
scientific domains. We find that the transformation is well described by a
power-law function, and that the parameter values of the transformation are
typical features of each scientific discipline. Universal properties of
citation patterns descend therefore from the fact that citation distributions
for papers in a specific field are all part of the same family of univariate
distributions.Comment: 9 pages, 6 figures. Supporting information files available at
http://filrad.homelinux.or
Search for Exotic Strange Quark Matter in High Energy Nuclear Reactions
We report on a search for metastable positively and negatively charged states
of strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864.
We have sampled approximately six billion 10% most central Au+Pb interactions
and have observed no strangelet states (baryon number A < 100 droplets of
strange quark matter). We thus set upper limits on the production of these
exotic states at the level of 1-6 x 10^{-8} per central collision. These limits
are the best and most model independent for this colliding system. We discuss
the implications of our results on strangelet production mechanisms, and also
on the stability question of strange quark matter.Comment: 21 pages, 9 figures, to be published in Nuclear Physics A (Carl Dover
memorial edition
Discrimination of low missing energy look-alikes at the LHC
The problem of discriminating possible scenarios of TeV scale new physics
with large missing energy signature at the Large Hadron Collider (LHC) has
received some attention in the recent past. We consider the complementary, and
yet unexplored, case of theories predicting much softer missing energy spectra.
As there is enough scope for such models to fake each other by having similar
final states at the LHC, we have outlined a systematic method based on a
combination of different kinematic features which can be used to distinguish
among different possibilities. These features often trace back to the
underlying mass spectrum and the spins of the new particles present in these
models. As examples of "low missing energy look-alikes", we consider
Supersymmetry with R-parity violation, Universal Extra Dimensions with both
KK-parity conserved and KK-parity violated and the Littlest Higgs model with
T-parity violated by the Wess-Zumino-Witten anomaly term. Through detailed
Monte Carlo analysis of the four and higher lepton final states predicted by
these models, we show that the models in their minimal forms may be
distinguished at the LHC, while non-minimal variations can always leave scope
for further confusion. We find that, for strongly interacting new particle
mass-scale ~600 GeV (1 TeV), the simplest versions of the different theories
can be discriminated at the LHC running at sqrt{s}=14 TeV within an integrated
luminosity of 5 (30) fb^{-1}.Comment: 40 pages, 10 figures; v2: Further discussions, analysis and one
figure added, ordering of certain sections changed, minor modifications in
the abstract, version as published in JHE
Beyond the standard seesaw: neutrino masses from Kahler operators and broken supersymmetry
We investigate supersymmetric scenarios in which neutrino masses are
generated by effective d=6 operators in the Kahler potential, rather than by
the standard d=5 superpotential operator. First, we discuss some general
features of such effective operators, also including SUSY-breaking insertions,
and compute the relevant renormalization group equations. Contributions to
neutrino masses arise at low energy both at the tree level and through finite
threshold corrections. In the second part we present simple explicit
realizations in which those Kahler operators arise by integrating out heavy
SU(2)_W triplets, as in the type II seesaw. Distinct scenarios emerge,
depending on the mechanism and the scale of SUSY-breaking mediation. In
particular, we propose an appealing and economical picture in which the heavy
seesaw mediators are also messengers of SUSY breaking. In this case, strong
correlations exist among neutrino parameters, sparticle and Higgs masses, as
well as lepton flavour violating processes. Hence, this scenario can be tested
at high-energy colliders, such as the LHC, and at lower energy experiments that
measure neutrino parameters or search for rare lepton decays.Comment: LaTeX, 34 pages; some corrections in Section
Immunodepletion of high-abundant proteins from acute and chronic wound fluids to elucidate low-abundant regulators in wound healing
<p>Abstract</p> <p>Background</p> <p>The process of wound healing consists of several well distinguishable and finely tuned phases. For most of these phases specific proteins have been characterized, although the underlying mechanisms of regulation are not yet fully understood. It is an open question as to whether deficits in wound healing can be traced back to chronic illnesses such as diabetes mellitus. Previous research efforts in this field focus largely on a restricted set of marker proteins due to the limitations detection by antibodies imposes. For mechanistic purposes the elucidation of differences in acute and chronic wounds can be addressed by a less restricted proteome study. Mass spectrometric (MS) methods, e.g. multi dimensional protein identification technology (MudPIT), are well suitable for this complex theme of interest. The human wound fluid proteome is extremely complex, as is human plasma. Therefore, high-abundant proteins often mask the mass spectrometric detection of lower-abundant ones, which makes a depletion step of such predominant proteins inevitable.</p> <p>Findings</p> <p>In this study a commercially available immunodepletion kit was evaluated for the detection of low-abundant proteins from wound fluids. The dynamic range of the entire workflow was significantly increased to 5-6 orders of magnitude, which makes low-abundant regulatory proteins involved in wound healing accessible for MS detection.</p> <p>Conclusion</p> <p>The depletion of abundant proteins is absolutely necessary in order to analyze highly complex protein mixtures such as wound fluids using mass spectrometry. For this the used immunodepletion kit is a first but important step in order to represent the entire dynamic range of highly complex protein mixtures in the future.</p
Management of venous thrombosis in fibular free osseomusculocutaneous flaps used for mandibular reconstruction: clinical techniques and treatment considerations
<p>Abstract</p> <p>Background</p> <p>Mandibular reconstruction by means of fibula transplants is the standard therapy for severe bone loss after subtotal mandibulectomy. Venous failure still represents the most common complication in free flap surgery. We present the injection of heparine into the arterial pedicle as modification of the revising both anastomoses in these cases and illustrate the application with a clinical case example.</p> <p>Methods</p> <p>Methods consist of immediate revision surgery with clot removal, heparin perfusion by direct injection in the arterial vessel of the pedicle, subsequent high dose low-molecular weight heparin therapy, and leeches. After 6 hours postoperatively, images of early flap recovery show first sings of recovery by fading livid skin color.</p> <p>Results</p> <p>The application of this technique in a patient with venous thrombosis resulted in the complete recovery of the flap 60 hours postoperatively. Other cases achieved similar success without additional lysis Therapy or revision of the arterial anastomosis.</p> <p>Conclusion</p> <p>Rescue of fibular flaps is possible even in patients with massive thrombosis if surgical revision is done quickly.</p
Identification of adults with symptoms suggestive of obstructive airways disease: Validation of a postal respiratory questionnaire
BACKGROUND: Two simples scoring systems for a self-completed postal respiratory questionnaire were developed to identify adults who may have obstructive airways disease. The objective of this study was to validate these scoring systems. METHOD: A two-stage design was used. All adults in two practice populations were sent the questionnaire and a stratified random sample of respondents was selected to undergo full clinical evaluation. Three respiratory physicians reviewed the results of each evaluation. A majority decision was reached as to whether the subject merited a trial of obstructive airways disease medication. This clinical decision was compared with two scoring systems based on the questionnaire in order to determine their positive predictive value, sensitivity and specificity. RESULTS: The PPV (positive predictive value) of the first scoring system was 75.1% (95% CI 68.6–82.3), whilst that of the second system was 82.3% (95% CI 75.9–89.2). The more stringent second system had the greater specificity, 97.1% (95% CI 96.0–98.2) versus 95.3% (95% CI 94.0–96.7), but poorer sensitivity 46.9% (95% CI 33.0–66.8) versus 50.3% (95% CI 35.3–71.6). CONCLUSION: This scoring system based on the number of symptoms/risk factors reported via a postal questionnaire could be used to identify adults who would benefit from a trial of treatment for obstructive airways disease
Interplay of LFV and slepton mass splittings at the LHC as a probe of the SUSY seesaw
We study the impact of a type-I SUSY seesaw concerning lepton flavour
violation (LFV) both at low-energies and at the LHC. The study of the di-lepton
invariant mass distribution at the LHC allows to reconstruct some of the masses
of the different sparticles involved in a decay chain. In particular, the
combination with other observables renders feasible the reconstruction of the
masses of the intermediate sleptons involved in decays. Slepton mass splittings can be either
interpreted as a signal of non-universality in the SUSY soft breaking-terms
(signalling a deviation from constrained scenarios as the cMSSM) or as being
due to the violation of lepton flavour. In the latter case, in addition to
these high-energy processes, one expects further low-energy manifestations of
LFV such as radiative and three-body lepton decays. Under the assumption of a
type-I seesaw as the source of neutrino masses and mixings, all these LFV
observables are related. Working in the framework of the cMSSM extended by
three right-handed neutrino superfields, we conduct a systematic analysis
addressing the simultaneous implications of the SUSY seesaw for both high- and
low-energy lepton flavour violation. We discuss how the confrontation of
slepton mass splittings as observed at the LHC and low-energy LFV observables
may provide important information about the underlying mechanism of LFV.Comment: 50 pages, 42 eps Figures, typos correcte
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