603 research outputs found
Behavioral Adjustment in Children with Life Threatening Illness A Qualitative Study
This study investigated factors that affect adjustment in children with life-threatening illness from the viewpoint of the parents/caregivers. The data were collected from parents/caregivers whose children have a life threatening diagnosis. Parents/caregivers were interviewed and asked to complete the Parent Request Questionnaire (PRQ) which was given to them after the in-person interview. This newly developed PRQ was utilized into prior research to predict the levels of adjustment in children. It includes age, whether the child has been informed of the diagnosis, whether the child engages in age-appropriate activities, the child\u27s prior experience with death, the child\u27s family\u27s involvement in treatment, and the child\u27s belief in an after-life. Prior literature suggests associations between these factors and the child\u27s ability to adjust to the diagnosis. This study examined these factors revealed by the parents/caregivers and any similarities were noted. There has been limited research conducted on behavioral adjustment in children with life threatening illness. This qualitative study utilized an open-ended interview process to gather information about the factors that promote behavioral adjustment and whether or not the factors already researched in quantitative studies applied. The interviewees were participants in independent support groups benefiting the caregivers/parents of the children with life threatening illness. Participants were also recruited by word-of-mouth after calling such groups and individuals in California. The PRQ was distributed after the interview as an additional measure. The interview revealed factors as noted by the caregivers and indicated the emergent themes of: isolation, fear, inquisitiveness, age-appropriate activities, diagnoses shared, and support systems. The interview and the PRQ were used to analyze child adjustment reported during the interview sessions. The participants in this study were all parents/caregivers. Instrumentation was a structured interview and a demographic questionnaire (PRQ). The texts were transcribed and analyzed using Thematic Analysis. Narratives of their life experience with the child having life-threatening illness were examined. Emergent themes, previously mentioned, were elicited from the interview material in hopes of providing additional support services needed as voiced by the parents/caregivers. “The electronic version of the dissertation is accessible at the Ohiolink ETD center http://www.ohiolink.edu/etd
Behavioral Adjustment in Children with Life Threatening Illness A Qualitative Study
This study investigated factors that affect adjustment in children with life-threatening illness from the viewpoint of the parents/caregivers. The data were collected from parents/caregivers whose children have a life threatening diagnosis. Parents/caregivers were interviewed and asked to complete the Parent Request Questionnaire (PRQ) which was given to them after the in-person interview. This newly developed PRQ was utilized into prior research to predict the levels of adjustment in children. It includes age, whether the child has been informed of the diagnosis, whether the child engages in age-appropriate activities, the child\u27s prior experience with death, the child\u27s family\u27s involvement in treatment, and the child\u27s belief in an after-life. Prior literature suggests associations between these factors and the child\u27s ability to adjust to the diagnosis. This study examined these factors revealed by the parents/caregivers and any similarities were noted. There has been limited research conducted on behavioral adjustment in children with life threatening illness. This qualitative study utilized an open-ended interview process to gather information about the factors that promote behavioral adjustment and whether or not the factors already researched in quantitative studies applied. The interviewees were participants in independent support groups benefiting the caregivers/parents of the children with life threatening illness. Participants were also recruited by word-of-mouth after calling such groups and individuals in California. The PRQ was distributed after the interview as an additional measure. The interview revealed factors as noted by the caregivers and indicated the emergent themes of: isolation, fear, inquisitiveness, age-appropriate activities, diagnoses shared, and support systems. The interview and the PRQ were used to analyze child adjustment reported during the interview sessions. The participants in this study were all parents/caregivers. Instrumentation was a structured interview and a demographic questionnaire (PRQ). The texts were transcribed and analyzed using Thematic Analysis. Narratives of their life experience with the child having life-threatening illness were examined. Emergent themes, previously mentioned, were elicited from the interview material in hopes of providing additional support services needed as voiced by the parents/caregivers. “The electronic version of the dissertation is accessible at the Ohiolink ETD center http://www.ohiolink.edu/etd
On the breaking of collinear factorization in QCD
We investigate the breakdown of collinear factorization for non-inclusive
observables in hadron-hadron collisions. For pure QCD processes, factorization
is violated at the three-loop level and it has a structure identical to that
encountered previously in the case of super-leading logarithms. In particular,
it is driven by the non-commutation of Coulomb/Glauber gluon exchanges with
other soft exchanges. Beyond QCD, factorization may be violated at the two-loop
level provided that the hard subprocess contains matrix element contributions
with phase differences between different colour topologies.Comment: Version 2: minor improvements for journal publicatio
Dirac-Hestenes spinor fields in Riemann-Cartan spacetime
In this paper we study Dirac-Hestenes spinor fields (DHSF) on a
four-dimensional Riemann-Cartan spacetime (RCST). We prove that these fields
must be defined as certain equivalence classes of even sections of the Clifford
bundle (over the RCST), thereby being certain particular sections of a new
bundle named Spin-Clifford bundle (SCB). The conditions for the existence of
the SCB are studied and are shown to be equivalent to the famous Geroch's
theorem concerning to the existence of spinor structures in a Lorentzian
spacetime. We introduce also the covariant and algebraic Dirac spinor fields
and compare these with DHSF, showing that all the three kinds of spinor fields
contain the same mathematical and physical information. We clarify also the
notion of (Crumeyrolle's) amorphous spinors (Dirac-K\"ahler spinor fields are
of this type), showing that they cannot be used to describe fermionic fields.
We develop a rigorous theory for the covariant derivatives of Clifford fields
(sections of the Clifford bundle (CB)) and of Dirac-Hestenes spinor fields. We
show how to generalize the original Dirac-Hestenes equation in Minkowski
spacetime for the case of a RCST. Our results are obtained from a variational
principle formulated through the multiform derivative approach to Lagrangian
field theory in the Clifford bundle.Comment: 45 pages, special macros kapproc.sty and makro822.te
On the renormalization of multiparton webs
We consider the recently developed diagrammatic approach to soft-gluon
exponentiation in multiparton scattering amplitudes, where the exponent is
written as a sum of webs - closed sets of diagrams whose colour and kinematic
parts are entangled via mixing matrices. A complementary approach to
exponentiation is based on the multiplicative renormalizability of intersecting
Wilson lines, and their subsequent finite anomalous dimension. Relating this
framework to that of webs, we derive renormalization constraints expressing all
multiple poles of any given web in terms of lower-order webs. We examine these
constraints explicitly up to four loops, and find that they are realised
through the action of the web mixing matrices in conjunction with the fact that
multiple pole terms in each diagram reduce to sums of products of lower-loop
integrals. Relevant singularities of multi-eikonal amplitudes up to three loops
are calculated in dimensional regularization using an exponential infrared
regulator. Finally, we formulate a new conjecture for web mixing matrices,
involving a weighted sum over column entries. Our results form an important
step in understanding non-Abelian exponentiation in multiparton amplitudes, and
pave the way for higher-loop computations of the soft anomalous dimension.Comment: 60 pages, 15 figure
An effective theory for jet propagation in dense QCD matter: jet broadening and medium-induced bremsstrahlung
Two effects, jet broadening and gluon bremsstrahlung induced by the
propagation of a highly energetic quark in dense QCD matter, are reconsidered
from effective theory point of view. We modify the standard Soft Collinear
Effective Theory (SCET) Lagrangian to include Glauber modes, which are needed
to implement the interactions between the medium and the collinear fields. We
derive the Feynman rules for this Lagrangian and show that it is invariant
under soft and collinear gauge transformations. We find that the newly
constructed theory SCET recovers exactly the general result for the
transverse momentum broadening of jets. In the limit where the radiated gluons
are significantly less energetic than the parent quark, we obtain a jet
energy-loss kernel identical to the one discussed in the reaction operator
approach to parton propagation in matter. In the framework of SCET we
present results for the fully-differential bremsstrahlung spectrum for both the
incoherent and the Landau-Pomeranchunk-Migdal suppressed regimes beyond the
soft-gluon approximation. Gauge invariance of the physics results is
demonstrated explicitly by performing the calculations in both the light-cone
and covariant gauges. We also show how the process-dependent
medium-induced radiative corrections factorize from the jet production cross
section on the example of the quark jets considered here.Comment: 52 pages, 15 pdf figures, as published in JHE
Damage control operations in non-trauma patients: Defining criteria for the staged rapid source control laparotomy in emergency general surgery
Background: The staged laparotomy in the operative management of emergency general surgery (EGS) patients is an extension of trauma surgeons operating on this population. Indications for its application, however, are not well defined, and are currently based on the lethal triad used in physiologically-decompensated trauma patients. This study sought to determine the acute indications for the staged, rapid source control laparotomy (RSCL) in EGS patients. Methods: All EGS patients undergoing emergent staged RSCL and non-RSCL over 3years were studied. Demographics, physiologic parameters, perioperative variables, outcomes, and survival were compared. Logistic regression models determined the influence of physiologic parameters on mortality and postoperative complications. EGS-RSCL indications were defined. Results: 215 EGS patients underwent emergent laparotomy; 53 (25%) were staged RSCL. In the 53 patients who underwent a staged RSCL based on the lethal triad, adjusted multivariable regression analysis shows that when used alone, no component of the lethal triad independently improved survival. Staged RSCL may decrease mortality in patients with preoperative severe sepsis / septic shock, and an elevated lactate (≥3); acidosis (pH ≤ 7.25); elderly (≥70); male gender; and multiple comorbidities (≥3). Of the 162 non-RSCL emergent laparotomies, 27 (17%) required unplanned re-explorations; of these, 17 (63%) had sepsis preoperatively and 9 (33%) died. Conclusions: The acute physiologic indicators that help guide operative decisions in trauma may not confer a similar survival advantage in EGS. To replace the lethal triad, criteria for application of the staged RSCL in EGS need to be defined. Based on these results, the indications should include severe sepsis / septic shock, lactate, acidosis, gender, age, and pre-existing comorbidities. When correctly applied, the staged RSCL may help to improve survival in decompensated EGS patients
From Webs to Polylogarithms
We compute a class of diagrams contributing to the multi-leg soft anomalous
dimension through three loops, by renormalizing a product of semi-infinite
non-lightlike Wilson lines in dimensional regularization. Using non-Abelian
exponentiation we directly compute contributions to the exponent in terms of
webs. We develop a general strategy to compute webs with multiple gluon
exchanges between Wilson lines in configuration space, and explore their
analytic structure in terms of , the exponential of the Minkowski
cusp angle formed between the lines and . We show that beyond the
obvious inversion symmetry , at the level of the
symbol the result also admits a crossing symmetry , relating spacelike and timelike kinematics, and hence argue that
in this class of webs the symbol alphabet is restricted to and
. We carry out the calculation up to three gluons connecting
four Wilson lines, finding that the contributions to the soft anomalous
dimension are remarkably simple: they involve pure functions of uniform weight,
which are written as a sum of products of polylogarithms, each depending on a
single cusp angle. We conjecture that this type of factorization extends to all
multiple-gluon-exchange contributions to the anomalous dimension.Comment: 64 pages, 8 figure
Constraints on the pMSSM from searches for squarks and gluinos by ATLAS
We study the impact of the jets and missing transverse momentum SUSY analyses
of the ATLAS experiment on the phenomenological MSSM (pMSSM). We investigate
sets of SUSY models with a flat and logarithmic prior in the SUSY mass scale
and a mass range up to 1 and 3 TeV, respectively. These models were found
previously in the study 'Supersymmetry without Prejudice'. Removing models with
long-lived SUSY particles, we show that 99% of 20000 randomly generated pMSSM
model points with a flat prior and 87% for a logarithmic prior are excluded by
the ATLAS results. For models with squarks and gluinos below 600 GeV all models
of the pMSSM grid are excluded. We identify SUSY spectra where the current
ATLAS search strategy is less sensitive and propose extensions to the inclusive
jets search channel
Space-like (vs. time-like) collinear limits in QCD: is factorization violated?
We consider the singular behaviour of QCD scattering amplitudes in
kinematical configurations where two or more momenta of the external partons
become collinear. At the tree level, this behaviour is known to be controlled
by factorization formulae in which the singular collinear factor is universal
(process independent). We show that this strict (process-independent)
factorization is not valid at one-loop and higher-loop orders in the case of
the collinear limit in space-like regions (e.g., collinear radiation from
initial-state partons). We introduce a generalized version of all-order
collinear factorization, in which the space-like singular factors retain some
dependence on the momentum and colour charge of the non-collinear partons. We
present explicit results on one-loop and two-loop amplitudes for both the
two-parton and multiparton collinear limits. At the level of square amplitudes
and, more generally, cross sections in hadron--hadron collisions, the violation
of strict collinear factorization has implications on the non-abelian structure
of logarithmically-enhanced terms in perturbative calculations (starting from
the next-to-next-to-leading order) and on various factorization issues of mass
singularities (starting from the next-to-next-to-next-to-leading order).Comment: 81 pages, 5 figures, typos corrected in the text, few comments added
and inclusion of NOTE ADDED on recent development
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