2,548 research outputs found
Macroscopic Floquet topological crystalline steel pump
The transport of a steel sphere on top of two dimensional periodic magnetic
patterns is studied experimentally. Transport of the sphere is achieved by
moving an external permanent magnet on a closed loop around the two dimensional
crystal. The transport is topological i.e. the steel sphere is transported by a
primitive unit vector of the lattice when the external magnet loop winds around
specific directions. We experimentally determine the set of directions the
loops must enclose for nontrivial transport of the steel sphere into various
directions
Beam manipulation for resonant plasma wakefield acceleration
Plasma-based acceleration has already proved the ability to reach ultra-high accelerating gradients. However
the step towards the realization of a plasma-based accelerator still requires some e
ff ort to guarantee high brightness beams, stability and reliability. A significant improvement in the efficiency of PWFA has been
demonstrated so far accelerating a witness bunch in the wake of a higher charge driver bunch. The transformer
ratio, therefore the energy transfer from the driver to the witness beam, can be increased by resonantly exciting
the plasma with a properly pre-shaped drive electron beam. Theoretical and experimental studies of beam
manipulation for resonant PWFA will be presented her
Vacuum oscillation solution to the solar neutrino problem in standard and non-standard pictures
The neutrino long wavelength (just-so) oscillation is revisited as a solution
to the solar neutrino problem. We consider just-so scenario in various cases:
in the framework of the solar models with relaxed prediction of the boron
neutrino flux, as well as in the presence of the non-standard weak range
interactions between neutrino and matter constituents. We show that the fit of
the experimental data in the just-so scenario is not very good for any
reasonable value of the neutrino flux, but it substantially improves if
the non-standard -neutrino--electron interaction is included. These new
interactions could also remove the conflict of the just-so picture with the
shape of the SN 1987A neutrino spectrum. Special attention is devoted to the
potential of the future real-time solar neutrino detectors as are
Super-Kamiokande, SNO and BOREXINO, which could provide the model independent
tests for the just-so scenario. In particular, these imply specific deformation
of the original solar neutrino energy spectra, and time variation of the
intermediate energy monochromatic neutrino ( and ) signals.Comment: Latex, 14 pages, 9 figures (avalilable by fax or postscript files
requested to [email protected]) -- some textual and Latex errors are corrected
and few references adde
Supersymmetric Seesaw without Singlet Neutrinos: Neutrino Masses and Lepton-Flavour Violation
We consider the supersymmetric seesaw mechanism induced by the exchange of
heavy SU(2)_W triplet states, rather than `right-handed' neutrino singlets, to
generate neutrino masses. We show that in this scenario the neutrino flavour
structure tested at low-energy in the atmospheric and solar neutrino
experiments is directly inherited from the neutrino Yukawa couplings to the
triplets. This allows us to predict the ratio of the tau --> mu gamma (or tau
--> e gamma) and mu --> e gamma decay rates in terms of the low-energy neutrino
parameters. Moreover, once the model is embedded in a grand unified model,
quark-flavour violation can be linked to lepton-flavour violation.Comment: 26 LaTeX pages, 10 postscript figures, uses epsfig and axodraw.
Comments and references adde
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
Caregivers' active role in palliative home care – to encourage or to dissuade? A qualitative descriptive study
<p>Abstract</p> <p>Background</p> <p>Spouses' involvement in palliative care is often a prerequisite for home death, but it is unclear whether active involvement of the spouse, e.g. administering and being in charge of oral or subcutaneous medication or taking care of the patient's personal hygiene, could be harmful or have negative effects on the spouse's experience of the palliative course of disease. The aim of this study was to explore the impact of bereaved spouses' active involvement in medical and physical care on their experience of the palliative course of disease.</p> <p>Methods</p> <p>The study was a qualitative, descriptive study based on semi-structured individual interviews with seven bereaved spouses.</p> <p>Results</p> <p>Four main categories were found: Degree of involvement, Positive and Negative impact and Prerequisites. The prerequisites found for a positive outcome were Safety (24-hour back-up), Confidence (Professionals' confidence in the spouses' abilities) and Dialog (Spouses' influence on decision-making and being asked).</p> <p>Conclusion</p> <p>The results from this study identified important issues whenever spouses take an active part in medical treatment and physical care of critically ill patients in palliative care. The results question the previous research that active involvement of family care givers could be harmful and add preconditions to a positive outcome. More research into these preconditions is needed.</p
Possible disease-modifying factors: the mannan-binding lectin pathway and infections in hereditary angioedema of children and adults
Redox proteomics of the inflammatory secretome identifies a common set of redoxins and other glutathionylated proteins released in inflammation, influenza virus infection and oxidative stress
Protein cysteines can form transient disulfides with glutathione (GSH), resulting in the production of glutathionylated proteins, and this process is regarded as a mechanism by which the redox state of the cell can regulate protein function. Most studies on redox regulation of immunity have focused on intracellular proteins. In this study we have used redox proteomics to identify those proteins released in glutathionylated form by macrophages stimulated with lipopolysaccharide (LPS) after pre-loading the cells with biotinylated GSH. Of the several proteins identified in the redox secretome, we have selected a number for validation. Proteomic analysis indicated that LPS stimulated the release of peroxiredoxin (PRDX) 1, PRDX2, vimentin (VIM), profilin1 (PFN1) and thioredoxin 1 (TXN1). For PRDX1 and TXN1, we were able to confirm that the released protein is glutathionylated. PRDX1, PRDX2 and TXN1 were also released by the human pulmonary epithelial cell line, A549, infected with influenza virus. The release of the proteins identified was inhibited by the anti-inflammatory glucocorticoid, dexamethasone (DEX), which also inhibited tumor necrosis factor (TNF)-α release, and by thiol antioxidants (N-butanoyl GSH derivative, GSH-C4, and N-acetylcysteine (NAC), which did not affect TNF-α production. The proteins identified could be useful as biomarkers of oxidative stress associated with inflammation, and further studies will be required to investigate if the extracellular forms of these proteins has immunoregulatory functions
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