330 research outputs found
Pre-Chemotherapy Differences in Visuospatial Working Memory in Breast Cancer Patients Compared to Controls: An fMRI Study
Introduction: Cognitive deficits are a side-effect of chemotherapy, however pre-treatment research is limited. This study examines neurofunctional differences during working memory between breast cancer (BC) patients and controls, prior to chemotherapy. Methods: Early stage BC females (23), scanned after surgery but before chemotherapy, were individually matched to non-cancer controls. Participants underwent functional magnetic resonance imaging (fMRI) while performing a Visuospatial N-back task and data was analyzed by multiple group comparisons. fMRI task performance, neuropsychological tests, hospital records, and salivary biomarkers were also collected. Results: There were no significant group differences on neuropsychological tests, estrogen, or cortisol. Patients made significantly fewer commission errors but had less overall correct responses and were slower than controls during the task. Significant group differences were observed for the fMRI data, yet results depended on the type of analysis. BC patients presented with increased activations during working memory compared to controls in areas such as the inferior frontal gyrus, insula, thalamus, and midbrain. Individual group regressions revealed a reverse relationship between brain activity and commission errors. Conclusion: This is the first fMRI investigation to reveal neurophysiological differences during visuospatial working memory between BC patients pre-chemotherapy and controls. These results also increase the knowledge about the effects of BC and related factors on the working memory network. Significance: This highlights the need to better understand the pre-chemotherapy BC patient and the effects of associated confounding variables
Infrared properties of exotic superconductors
The infrared spectra of the non-traditional superconductors share certain
common features. The lack of a gap signature at and the residual
conductivity are the consequence of a d-wave order parameter. The high
materials, the organic conductors and the heavy Fermion materials have a strong
mid-infrared absorption band which can be interpreted as strong coupling of the
carriers to electronic degrees of freedom which leads to a breakdown of the
Fermi liquid picture. The cuprates and the organic charge transfer salts are
unique in possessing an intrinsic low dimensionality. The charge transport
normal to the highly conducting direction is incoherent down to the lowest
temperatures and frequencies.Comment: 10 pages 11 figures, From the proceedings of the First Euroconference
on Anomalous Complex Superconductors, Heraklion, Crete. Sept 1998, to be
published in Physica
A mixed methods evaluation of the largescale implementation of a school- and community-based parenting program to reduce violence against children in Tanzania: a study protocol
Despite the rapid dissemination of parenting programs aiming to reduce and prevent violence
against children (VAC) worldwide, there is limited knowledge about and evidence of the implementation of these
programs at scale. This study addresses this gap by assessing the quality of delivery and impact of an evidencebased parenting program for parents/caregivers and their adolescent girls aged 9 to 14âParenting for Lifelong
Health Teens (PLH-Teens), known locally as Furaha Teensâon reducing VAC at scale in Tanzania. The study will
explore participating family and staff perspectives on program implementation and examine factors associated with
implementation and how implementation quality is associated with intervention outcomes when the program is
delivered to approximately 50,000 parent-child dyads (N = 100,000) in schools and community centers across eight
districts of Tanzania
Geometric Transitions on non-Kaehler Manifolds
This article is based on the author's PhD--thesis. We study geometric
transitions on the supergravity level using the basic idea of
arXiv:hep-th/0403288, where a pair of non-Kaehler backgrounds was constructed,
which are related by a geometric transition. Here we embed this idea into an
orientifold setup as suggested in arXiv:hep-th/0511099. The non-Kaehler
backgrounds we obtain in type IIA are non-trivially fibered due to their
construction from IIB via T-duality with Neveu-Schwarz flux. We demonstrate
that these non-Kaehler manifolds are not half-flat and show that a symplectic
structure exists on them at least locally.
We also review the construction of new non-Kaehler backgrounds in type I and
heterotic theory as proposed in arXiv:hep-th/0408192. They are found by a
series of T- and S-duality and can be argued to be related by geometric
transitions as well. A local toy model is provided that fulfills the flux
equations of motion in IIB and the torsional relation in heterotic theory, and
that is consistent with the U-duality relating both theories. For the heterotic
theory we also propose a global solution that fulfills the torsional relation
because it is similar to the Maldacena-Nunez background.Comment: 127 pages, based on PhD-thesis, v2 some references added, this
version to appear in Fort. Phy
Renormalized couplings and scaling correction amplitudes in the N-vector spin models on the sc and the bcc lattices
For the classical N-vector model, with arbitrary N, we have computed through
order \beta^{17} the high temperature expansions of the second field derivative
of the susceptibility \chi_4(N,\beta) on the simple cubic and on the body
centered cubic lattices. (The N-vector model is also known as the O(N)
symmetric classical spin Heisenberg model or, in quantum field theory, as the
lattice
O(N) nonlinear sigma model.) By analyzing the expansion of \chi_4(N,\beta) on
the two lattices, and by carefully allowing for the corrections to scaling, we
obtain updated estimates of the critical parameters and more accurate tests of
the hyperscaling relation d\nu(N) +\gamma(N) -2\Delta_4(N)=0 for a range of
values of the spin dimensionality N, including
N=0 [the self-avoiding walk model], N=1 [the Ising spin 1/2 model],
N=2 [the XY model], N=3 [the classical Heisenberg model]. Using the recently
extended series for the susceptibility and for the second correlation moment,
we also compute the dimensionless renormalized four point coupling constants
and some universal ratios of scaling correction amplitudes in fair agreement
with recent renormalization group estimates.Comment: 23 pages, latex, no figure
Assessing the feasibility, acceptability, and fidelity of a tele-retinopathy-based intervention to encourage greater attendance to diabetic retinopathy screening in immigrants living with diabetes from China and African-Caribbean countries in Ottawa, Canada: a protocol
Background:
Diabetic retinopathy is a leading cause of preventable blindness in Canada. Clinical guidelines recommend annual diabetic retinopathy screening for people living with diabetes to reduce the risk and progression of vision loss. However, many Canadians with diabetes do not attend screening. Screening rates are even lower in immigrants to Canada including people from China, Africa, and the Caribbean, and these groups are also at higher risk of developing diabetes complications. We aim to assess the feasibility, acceptability, and fidelity of a co-developed, linguistically and culturally tailored tele-retinopathy screening intervention for Mandarin-speaking immigrants from China and French-speaking immigrants from African-Caribbean countries living with diabetes in Ottawa, Canada, and identify how many from each population group attend screening during the pilot period.
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Methods:
We will work with our health system and patient partners to conduct a 6-month feasibility pilot of a tele-retinopathy screening intervention in a Community Health Centre in Ottawa. We anticipate recruiting 50â150 patients and 5â10 health care providers involved in delivering the intervention for the pilot. Acceptability will be assessed via a Theoretical Framework of Acceptability-informed survey with patients and health care providers. To assess feasibility, we will use a Theoretical Domains Framework-informed interview guide and to assess fidelity, and we will use a survey informed by the National Institutes of Health framework from the perspective of health care providers. We will also collect patient demographics (i.e., age, gender, ethnicity, health insurance status, and immigration information), screening outcomes (i.e., patients with retinopathy identified, patients requiring specialist care), patient costs, and other intervention-related variables such as preferred language. Survey data will be descriptively analyzed and qualitative data will undergo content analysis.
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Discussion:
This feasibility pilot study will capture how many people living with diabetes from each group attend the diabetic retinopathy screening, costs, and implementation processes for the tele-retinopathy screening intervention. The study will indicate the practicability and suitability of the intervention in increasing screening attendance in the target population groups. The study results will inform a patient-randomized trial, provide evidence to conduct an economic evaluation of the intervention, and optimize the community-based intervention
Semi-Analytical Approaches to Local Electroweak Baryogenesis
We examine two semi-analytical methods for estimating the baryon asymmetry of
the universe (BAU) generated in scenarios of ``local'' electroweak baryogenesis
(in which the requisite baryon number violation and CP violation occur together
in space and time). We work with the standard electroweak theory augmented by
the addition of a CP violating dimension six operator. We work in the context
of a first order phase transition, but the processes we describe can also occur
during the evolution of a network of topological defects. Both the approaches
we explore deal with circumstances where the bubble walls which convert the
high temperature phase to the low temperature phase are thin and rapidly
moving. We first consider the dynamics of localized configurations with winding
number one which remain in the broken phase immediately after the bubble wall
has passed. Their subsequent decay can anomalously produce fermions. In a
prelude to our analysis of this effect, we demonstrate how to define the C and
CP symmetries in the bosonic sector of the electroweak theory when
configurations with nonzero winding are taken into account. Second, we consider
the effect of the passage of the wall itself on configurations which happen to
be near the crest of the ridge between vacua as the wall arrives. We find that
neither of the simple approaches followed here can be pushed far enough to
obtain a convincing estimate of the BAU which is produced. A large scale
numerical treatment seems necessary.Comment: 31 pages, revtex, one figure, epsf. This is the version to appear in
Phys Rev D; only changes are small clarification
Perception of medical professionalism among the surgical community in the University of Nairobi: a mixed method study
Laboratories, laws, and the career of a commodity
Unlike most foods, milk is produced fresh at least twice every day, thus recreating, over 700 times a year, a commodity âdesignedâ by the combination of nature, commerce, and law. The paper is a study of the ontogenesis of this commodity in Britain since 1800, stressing the emergence of two new objectivities: dairy science and the law on adulteration. In the words of Christopher Hamlin, what mattered was the âmanufacture of certainty, however flimsy that certainty might later be shown to be.'' This was achieved by the collection of samples, the generation of facts by the deployment of the laboratory technologies of physics and chemistry, and a semimonopoly over the truth-power of dairy science that was gradually built up by the large commercial companies. A foundation of state-sponsored regulation provided an official legitimation of compositional standards that suited the interests of capital but ignored ânaturalâ variations in quality and often pilloried innocent producers. The public eventually became accustomed to the regulated quality of the milk in its âpintaâ and assumed it to be natural. Even the standardization of composition since 1993 has caused very little disquiet among the consuming public, although milk is now a fully constructed commodity like any other dairy product. Mechanical modernity has at last triumphed over a century of âmilk as it came from the cowâ
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