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Search Results: 1 - 10 of 604438 matches for " Andrea M. J. Weiner "
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Fishing the Molecular Bases of Treacher Collins Syndrome
Andrea M. J. Weiner, Nadia L. Scampoli, Nora B. Calcaterra
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0029574
Abstract: Treacher Collins syndrome (TCS) is an autosomal dominant disorder of craniofacial development, and mutations in the TCOF1 gene are responsible for over 90% of TCS cases. The knowledge about the molecular mechanisms responsible for this syndrome is relatively scant, probably due to the difficulty of reproducing the pathology in experimental animals. Zebrafish is an emerging model for human disease studies, and we therefore assessed it as a model for studying TCS. We identified in silico the putative zebrafish TCOF1 ortholog and cloned the corresponding cDNA. The derived polypeptide shares the main structural domains found in mammals and amphibians. Tcof1 expression is restricted to the anterior-most regions of zebrafish developing embryos, similar to what happens in mouse embryos. Tcof1 loss-of-function resulted in fish showing phenotypes similar to those observed in TCS patients, and enabled a further characterization of the mechanisms underlying craniofacial malformation. Besides, we initiated the identification of potential molecular targets of treacle in zebrafish. We found that Tcof1 loss-of-function led to a decrease in the expression of cellular proliferation and craniofacial development. Together, results presented here strongly suggest that it is possible to achieve fish with TCS-like phenotype by knocking down the expression of the TCOF1 ortholog in zebrafish. This experimental condition may facilitate the study of the disease etiology during embryonic development.
A Brief Parametric Analysis of Catastrophic or Disastrous Hurricanes That Have Hit the Florida Keys between 1900 and 2000  [PDF]
J. M. D’Andrea
American Journal of Computational Mathematics (AJCM) , 2018, DOI: 10.4236/ajcm.2018.81001
Abstract: The most intense and catastrophic hurricanes on record to hit the Florida Keys during 1900 to 1950 were in 1919, and 1935. From 1950 to 2000, the most intense hurricanes to hit or affect the Florida Keys were in 1960, 1965, and 1992. In this paper, we will present a brief parametric analysis of the hurricanes that have hit the Florida Keys in the last 100 years. This analysis will include the descriptive statistics, best fit probability distribution of the latitude of the catastrophic hurricanes and a confidence interval that detects the average latitude of hurricanes (category 3 or higher) which have hit the Florida Keys in the last 100 years.
Comments on "Observation of Long-Range, Near-Side Angular Correlations in Proton-Proton Collisions at the LHC" by the CMS collaboration(arXiv:1009.4122v1 [hep-ex])"
Michael J. Tannenbaum,Richard M. Weiner
Physics , 2010,
Abstract: It is the purpose of this note to point out that the CMS observation is in line with previous observations in particle physics at large transverse momenta and/or high multiplicities at lower energies, which were interpreted as possible evidence for quark-gluon plasma (QGP), and to suggest other features of the QGP observed in A+A collisions such as radial flow and jet quenching, which should be investigated in p-p collisions in order to provide further evidence for QGP production.
Implementing community-based provider participation in research: an empirical study
Randall Teal, Dawn M Bergmire, Matthew Johnston, Bryan J Weiner
Implementation Science , 2012, DOI: 10.1186/1748-5908-7-41
Abstract: We used longitudinal, case study research methods and an organizational model of innovation implementation to theoretically guide our study. Our sample consisted of three community practice settings that recently joined the National Cancer Institute’s (NCI) Community Clinical Oncology Program (CCOP) in the United States. Data were gathered through site visits, telephone interviews, and archival documents from January 2008 to May 2011.The organizational model for innovation implementation was useful in identifying and investigating the organizational factors influencing start-up and early implementation of CBPPR in CCOP organizations. In general, the three CCOP organizations varied in the extent to which they achieved consistency in CBPPR over time and across physicians. All three CCOP organizations demonstrated mixed levels of organizational readiness for change. Hospital management support and resource availability were limited across CCOP organizations early on, although they improved in one CCOP organization. As a result of weak IPPs, all three CCOPs created a weak implementation climate. Patient accrual became concentrated over time among those groups of physicians for whom CBPPR exhibited a strong innovation-values fit. Several external factors influenced innovation use, complicating and enriching our intra-organizational model of innovation implementation.Our results contribute to the limited body of research on the implementation of CBPPR. They inform policy discussions about increasing and sustaining community clinician involvement in clinical research and expand on theory about organizational determinants of implementation effectiveness.
Comment on ``Enhanced transmission of light through a gold film due to excitation of standing surface-plasmon Bloch waves"
J. Weiner
Physics , 2007, DOI: 10.1103/PhysRevB.77.036401
Abstract: The purpose of this comment is first to correct a misapprehension of the role played by composite wave diffraction on surface-wave generation at subwavelength structures and second to point out that periodic Bloch structures are unnecessary for the efficient production of the surface plasmon polariton (SPP) guided mode either as traveling or standing waves. Guided surface waves originate from simple slit or groove edges illuminated under normal incidence, and one-dimensional (1-D) surface cavities from these standing waves are easily realized.
Dark Matter Direct Detection with Non-Maxwellian Velocity Structure
M. Kuhlen,N. Weiner,J. Diemand,P. Madau,B. Moore,D. Potter,J. Stadel,M. Zemp
Physics , 2009, DOI: 10.1088/1475-7516/2010/02/030
Abstract: The velocity distribution function of dark matter particles is expected to show significant departures from a Maxwell-Boltzmann distribution. This can have profound effects on the predicted dark matter - nucleon scattering rates in direct detection experiments, especially for dark matter models in which the scattering is sensitive to the high velocity tail of the distribution, such as inelastic dark matter (iDM) or light (few GeV) dark matter (LDM), and for experiments that require high energy recoil events, such as many directionally sensitive experiments. Here we determine the velocity distribution functions from two of the highest resolution numerical simulations of Galactic dark matter structure (Via Lactea II and GHALO), and study the effects for these scenarios. For directional detection, we find that the observed departures from Maxwell-Boltzmann increase the contrast of the signal and change the typical direction of incoming DM particles. For iDM, the expected signals at direct detection experiments are changed dramatically: the annual modulation can be enhanced by more than a factor two, and the relative rates of DAMA compared to CDMS can change by an order of magnitude, while those compared to CRESST can change by a factor of two. The spectrum of the signal can also change dramatically, with many features arising due to substructure. For LDM the spectral effects are smaller, but changes do arise that improve the compatibility with existing experiments. We find that the phase of the modulation can depend upon energy, which would help discriminate against background should it be found.
Surface-wave interferometry on single subwavelength slit-groove structures fabricated on gold films
F. Kalkum,G. Gay,O. Alloschery,J. Weiner,H. J. Lezec,Y. Xie,M. Mansuripur
Physics , 2006, DOI: 10.1364/OE.15.002613
Abstract: We apply the technique of far-field interferometry to measure the properties of surface waves generated by two-dimensional (2D) single subwavelength slit-groove structures on gold films. The effective surface index of refraction measured for the surface wave propagating over a distance of more than 12 microns is determined to be 1.016 with a measurement uncertainty of 0.004, to within experimental uncertainty of the expected bound surface plasmon-polariton (SPP) value for a Au/Air interface of 1.018. We compare these measurements to finite-difference-time-domain (FDTD) numerical simulations of the optical field transmission through these devices. We find excellent agreement between the measurements and the simulations for the surface index of refraction. The measurements also show that the surface wave propagation parameter exhibits transient behavior close to the slit, evolving smoothly from greater values asymptotically toward the value expected for the SPP over the first 2-3 microns of slit-groove distance. This behavior is confirmed by the FDTD simulations.
Analysis of surface waves generated on subwavelength-structured silver films
G. Gay,O. Alloschery,J. Weiner,H. J. Lezec,C. O'Dwyer,M. Sukharev,T. Seideman
Physics , 2006, DOI: 10.1103/PhysRevE.75.016612
Abstract: Using transmission electron microscopy (TEM) to analyse the physical-chemical surface properties of subwavlength structured silver films and finite-difference time-domain (FDTD) numerical simulations of the optical response of these structures to plane-wave excitation, we report on the origin and nature of the persistent surface waves generated by a single slit-groove motif and recently measured by far-field optical interferometry. The surface analysis shows that the silver films are free of detectable oxide or sulfide contaminants, and the numerical simulations show very good agreement with the results previously reported.
The meaning and measurement of implementation climate
Bryan J Weiner, Charles M Belden, Dawn M Bergmire, Matthew Johnston
Implementation Science , 2011, DOI: 10.1186/1748-5908-6-78
Abstract: Implementation climate differs from constructs such as organizational climate, culture, or context in two important respects: first, it has a strategic focus (implementation), and second, it is innovation-specific. Measuring implementation climate is challenging because the construct operates at the organizational level, but requires the collection of multi-dimensional perceptual data from many expected innovation users within an organization. In order to avoid problems with construct validity, assessments of within-group agreement of implementation climate measures must be carefully considered. Implementation climate implies a high degree of within-group agreement in climate perceptions. However, researchers might find it useful to distinguish implementation climate level (the average of implementation climate perceptions) from implementation climate strength (the variability of implementation climate perceptions). It is important to recognize that the implementation climate construct applies most readily to innovations that require collective, coordinated behavior change by many organizational members both for successful implementation and for realization of anticipated benefits. For innovations that do not possess these attributes, individual-level theories of behavior change could be more useful in explaining implementation effectiveness.This construct has considerable value in implementation science, however, further debate and development is necessary to refine and distinguish the construct for empirical use.Katherine Klein and Joann Sorra's [1] theory of innovation implementation has become increasingly prominent in the field of implementation science. The article in which the theory first appeared has been cited 258 times since its publication in 1996. Reflecting the theory's popularity in health and human services research, one-third of the 258 citing articles focus on innovation implementation in hospitals, physician practices, community health centers, su
MRI Shows More Severe Hippocampal Atrophy and Shape Deformation in Hippocampal Sclerosis Than in Alzheimer's Disease
C. Zarow,L. Wang,H. C. Chui,M. W. Weiner,J. G. Csernansky
International Journal of Alzheimer's Disease , 2011, DOI: 10.4061/2011/483972
Abstract: While hippocampal atrophy is a key feature of both hippocampal sclerosis (HS) and Alzheimer's disease (AD), the pathology underlying this finding differs in these two conditions. In AD, atrophy is due primarily to loss of neurons and neuronal volume as a result of neurofibrillary tangle formation. While the etiology of HS is unknown, neuron loss in the hippocampus is severe to complete. We compared hippocampal volume and deformations from premortem MRI in 43 neuropathologically diagnosed cases of HS, AD, and normal controls (NC) selected from a longitudinal study of subcortical ischemic vascular disease (IVD Program Project). HS cases ( ) showed loss of neurons throughout the rostral-caudal extent of the hippocampus in one or both hemispheres. AD cases ( ) met NIA-Reagan criteria for high likelihood of AD. Normal control cases ( ) were cognitively intact and showed no significant AD or hippocampal pathology. The mean hippocampal volumes were significantly lower in HS versus AD groups ( ). Mean shape deformations in the CA1 and subiculum differed significantly between HS versus AD, HS versus NC, and AD versus NC ( ). Additional study is needed to determine whether these differences will be meaningful for clinical diagnosis of individual cases. 1. Introduction Hippocampal sclerosis (HS) is a highly prevalent pathologic lesion, found in approximately 15% of elderly dementia cases in autopsy series [1]. It is a common cause of memory loss in late life, but is rarely diagnosed before autopsy. HS is characterized by selective neuronal loss with gliosis in the absence of cystic cavitation, involving the CA1 sector of the hippocampus and often extending into the subiculum. A sharp demarcation is often noted histologically between affected and adjacent normal hippocampal subfields. HS can affect one or both hemispheres and can be focal or widespread in its rostral-caudal extent [2]. HS is often accompanied by other types of pathology, but may occur as a relatively isolated finding [1]. The pathogenesis of HS is not well understood, and ischemia/hypoxia, neurodegeneration, or a combination of these nonmutually exclusive processes has been postulated. A clinical diagnosis of HS is rarely made in late life. Most HS cases are discovered at autopsy and were diagnosed clinically as AD. The typical hallmarks of HS seen in early adulthood (namely, partial complex seizures and T-2 hyperintensity in the hippocampus) are absent in late-onset HS [3–5]. While hippocampal atrophy is the sine qua non of AD, it is also observed in HS. Late-life HS is associated with hippocampal
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