321 research outputs found
Dose-adapted post-transplant cyclophosphamide for HLA-haploidentical transplantation in Fanconi anemia.
We developed a haploidentical transplantation protocol with post-transplant cyclophosphamide (CY) for in vivo T-cell depletion (TCD) using a novel adapted-dosing schedule (25âmg/kg on days +3 and +4) for Fanconi anemia (FA). With median follow-up of 3 years (range, 37 days to 6.2 years), all six patients engrafted. Two patients with multiple pre-transplant comorbidities died, one from sepsis and one from sepsis with associated chronic GVHD. Four patients without preexisting comorbidities and early transplant referrals are alive with 100% donor chimerism and excellent performance status. We conclude that adjusted-dosing post-transplant CY is effective in in vivo TCD to promote full donor engraftment in patients with FA
Path integral formulation of Hodge duality on the brane
In the warped compactification with a single Randall-Sundrum brane, a
puzzling claim has been made that scalar fields can be bound to the brane but
their Hodge dual higher-rank anti-symmetric tensors cannot. By explicitly
requiring the Hodge duality, a prescription to resolve this puzzle was recently
proposed by Duff and Liu. In this note, we implement the Hodge duality via path
integral formulation in the presence of the background gravity fields of warped
compactifications. It is shown that the prescription of Duff and Liu can be
naturally understood within this framework.Comment: 7 pages, LaTe
Relating Quantum Information to Charged Black Holes
Quantum non-cloning theorem and a thought experiment are discussed for
charged black holes whose global structure exhibits an event and a Cauchy
horizon. We take Reissner-Norstr\"{o}m black holes and two-dimensional dilaton
black holes as concrete examples. The results show that the quantum non-cloning
theorem and the black hole complementarity are far from consistent inside the
inner horizon. The relevance of this work to non-local measurements is briefly
discussed.Comment: 14 pages, 2 figure
Black Hole Horizons and Complementarity
We investigate the effect of gravitational back-reaction on the black hole
evaporation process. The standard derivation of Hawking radiation is
re-examined and extended by including gravitational interactions between the
infalling matter and the outgoing radiation. We find that these interactions
lead to substantial effects. In particular, as seen by an outside observer,
they lead to a fast growing uncertainty in the position of the infalling matter
as it approaches the horizon. We argue that this result supports the idea of
black hole complementarity, which states that, in the description of the black
hole system appropriate to outside observers, the region behind the horizon
does not establish itself as a classical region of space-time. We also give a
new formulation of this complementarity principle, which does not make any
specific reference to the location of the black hole horizon.Comment: Some minor modifications in text and the title chang
Model of black hole evolution
From the postulate that a black hole can be replaced by a boundary on the
apparent horizon with suitable boundary conditions, an unconventional scenario
for the evolution emerges. Only an insignificant fraction of energy of order
is radiated out. The outgoing wave carries a very small part of the
quantum mechanical information of the collapsed body, the bulk of the
information remaining in the final stable black hole geometry.Comment: 9 pages, harvmac, 3 figures, minor addition
Model of black hole evolution
From the postulate that a black hole can be replaced by a boundary on the
apparent horizon with suitable boundary conditions, an unconventional scenario
for the evolution emerges. Only an insignificant fraction of energy of order
is radiated out. The outgoing wave carries a very small part of the
quantum mechanical information of the collapsed body, the bulk of the
information remaining in the final stable black hole geometry.Comment: 9 pages, harvmac, 3 figures, minor addition
Using paleoclimate reconstructions to analyse hydrological epochs associated with Pacific decadal variability
The duration of dry or wet hydrological epochs (run lengths) associated with
positive or negative Inter-decadal Pacific Oscillation (IPO) or Pacific Decadal Oscillation (PDO) phases, termed Pacific decadal variability (PDV), is an
essential statistical property for understanding, assessing and managing
hydroclimatic risk. Numerous IPO and PDO paleoclimate reconstructions provide
a valuable opportunity to study the statistical signatures of PDV, including
run lengths. However, disparities exist between these reconstructions, making
it problematic to determine which reconstruction(s) to use to investigate
pre-instrumental PDV and run length. Variability and persistence on
centennial scales are also present in some millennium-long reconstructions,
making consistent run length extraction difficult. Thus, a robust method to
extract meaningful and consistent run lengths from multiple reconstructions
is required. In this study, a dynamic threshold framework to account for
centennial trends in PDV reconstructions is proposed. The dynamic threshold
framework is shown to extract meaningful run length information from multiple
reconstructions. Two hydrologically important aspects of the statistical
signatures associated with the PDV are explored: (i)Â whether persistence
(i.e. run lengths) during positive epochs is different to persistence during
negative epochs and (ii)Â whether the reconstructed run lengths have been
stationary during the past millennium. Results suggest that there is no
significant difference between run lengths in positive and negative phases of
PDV and that it is more likely than not that the PDV run length has been
non-stationary in the past millennium. This raises concerns about whether
variability seen in the instrumental record (the last âŒ100 years), or
even in the shorter 300â400-year paleoclimate reconstructions, is
representative of the full range of variability.</p
On 't Hooft's S-matrix Ansatz for quantum black holes
The S-matrix Ansatz has been proposed by 't Hooft to overcome difficulties
and apparent contradictions of standard quantum field theory close to the black
hole horizon. In this paper we revisit and explore some of its aspects. We
start by computing gravitational backreaction effects on the properties of the
Hawking radiation and explain why a more powerful formalism is needed to encode
them. We then use the map bulk-boundary fields to investigate the nature of
exchange algebras satisfied by operators associated with ingoing and outgoing
matter. We propose and comment on some analogies between the non covariant form
of the S-matrix amplitude and liquid droplet physics to end up with
similarities with string theory amplitudes via an electrostatic analogy. We
finally recall the difficulties that one encounters when trying to incorporate
non linear gravity effects in 't Hooft's S-matrix and observe how the inclusion
of higher order derivatives might help in the black hole microstate counting.Comment: 22 Pages. Latex Fil
De Sitter Holography with a Finite Number of States
We investigate the possibility that, in a combined theory of quantum
mechanics and gravity, de Sitter space is described by finitely many states.
The notion of observer complementarity, which states that each observer has
complete but complementary information, implies that, for a single observer,
the complete Hilbert space describes one side of the horizon. Observer
complementarity is implemented by identifying antipodal states with outgoing
states. The de Sitter group acts on S-matrix elements. Despite the fact that
the de Sitter group has no nontrivial finite-dimensional unitary
representations, we show that it is possible to construct an S-matrix that is
finite-dimensional, unitary, and de Sitter-invariant. We present a class of
examples that realize this idea holographically in terms of spinor fields on
the boundary sphere. The finite dimensionality is due to Fermi statistics and
an `exclusion principle' that truncates the orthonormal basis in which the
spinor fields can be expanded.Comment: 23 pages, 1 eps figure, LaTe
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