6,777 research outputs found
Disseminated eruptive giant mollusca contagiosa in an adult psoriasis patient during efalizumab therapy
Molluscum contagiosum is a common viral skin infection in children with atopic diathesis and not rare in HIV patients. We report a 45-year-old psoriasis patient who developed eruptive mollusca contagiosa during an antipsoriatic treatment with efalizumab. Copyright (C) 2008 S. Karger AG, Basel
Parametric Probability Distribution Functions for Axon Diameters of Corpus Callosum
Axon diameter is an important neuroanatomical characteristic of the nervous system that alters in the course of neurological disorders such as multiple sclerosis. Axon diameters vary, even within a fiber bundle, and are not normally distributed. An accurate distribution function is therefore beneficial, either to describe axon diameters that are obtained from a direct measurement technique (e.g., microscopy), or to infer them indirectly (e.g., using diffusion-weighted MRI). The gamma distribution is a common choice for this purpose (particularly for the inferential approach) because it resembles the distribution profile of measured axon diameters which has been consistently shown to be non-negative and right-skewed. In this study we compared a wide range of parametric probability distribution functions against empirical data obtained from electron microscopy images. We observed that the gamma distribution fails to accurately describe the main characteristics of the axon diameter distribution, such as location and scale of the mode and the profile of distribution tails. We also found that the generalized extreme value distribution consistently fitted the measured distribution better than other distribution functions. This suggests that there may be distinct subpopulations of axons in the corpus callosum, each with their own distribution profiles. In addition, we observed that several other distributions outperformed the gamma distribution, yet had the same number of unknown parameters; these were the inverse Gaussian, log normal, log logistic and Birnbaum-Saunders distributions
Targeted search for the kinematic dipole of the gravitational-wave background
There is growing interest in using current and future gravitational-wave
interferometers to search for anisotropies in the gravitational-wave
background. One guaranteed anisotropic signal is the kinematic dipole induced
by our peculiar motion with respect to the cosmic rest frame, as measured in
other full-sky observables such as the cosmic microwave background. Our prior
knowledge of the amplitude and direction of this dipole is not explicitly
accounted for in existing searches by LIGO/Virgo/KAGRA, but could provide
crucial information to help disentangle the sources which contribute to the
gravitational-wave background. Here we develop a targeted search pipeline which
uses this prior knowledge to enable unbiased and minimum-variance inference of
the dipole magnitude. Our search generalises existing methods to allow for a
time-dependent signal model, which captures the annual modulation of the dipole
due to the Earth's orbit. We validate our pipeline on mock data, demonstrating
that neglecting this time dependence can bias the inferred dipole by as much as
. We then run our analysis on the full LIGO/Virgo O1+O2+O3 dataset,
obtaining upper limits on the dipole amplitude that are consistent with
existing anisotropic search results.Comment: 12 pages, 3 figure
A piece of the puzzle: analyses of recent strandings and historical records reveal new genetic and ecological insights on New Zealand sperm whales
Cetacean strandings provide important opportunities to extend current knowledge on species or populations, particularly for species that are notoriously difficult to study, such as sperm whales Physeter macrocephalus (parāoa). Between 25 May and 9 June 2018, 13 male sperm whales stranded in Taranaki, New Zealand (NZ), with an additional male stranding 1 mo later in Clifford Bay, Marlborough. We profiled these 14 males for mitochondrial DNA (mtDNA) and carbon and nitrogen stable isotopes to examine their similarity to sperm whales from other geographic areas. Analyses of mtDNA revealed 7 haplotypes, including 1 not previously described (‘New’), and an additional haplotype (‘M’) new to NZ that had been previously reported in sperm whales of the Pacific region. Analysis of rare haplotypes found in NZ males suggested genetic links within NZ and the Southwest Pacific. Differences in stable isotope ratios indicated that, despite the close temporal proximity of these stranding events, individuals originated from at least 2 separate groups, with the whale stranded in Clifford Bay identified as being a regular visitor to Kaikōura, South Island. The analysis of stranding records in NZ dating back to 1873 indicated an increase in recorded single strandings since 1970, and a peak in single strandings in the austral summer months, but no seasonality for mass strandings. Sex predicted latitudinal location for single strandings, with 95.1% of female strandings occurring north of 42° S, fitting the general global distribution of female sperm whales limited to lower latitudes. This study provides the first temporal and spatial assessment of sperm whale strandings in NZ and highlights the need for future research on movements and genetic exchange between NZ sperm whales and sperm whales in the wider Pacific region.Publishe
Lack of trust in maternal support is associated with negative interpretations of ambiguous maternal behavior
Attachment theory assumes that children who lack trust in maternal availability for support are more inclined to interpret maternal behavior in congruence with their expectation that mother will remain unavailable for support. To provide the first test of this assumption, early adolescents (9-13 years old) were asked to assess whether ambiguous interactions with mother should be interpreted in a positive or a negative way. In our sample (n = 322), results showed that early adolescents' lack of trust in their mother's availability for support was related to more negative interpretations of maternal behavior. The associations remained significant after controlling for depressive mood. The importance of these findings for our understanding of attachment theory, attachment stability, and clinical practice are discussed
The Minimal Scale Invariant Extension of the Standard Model
We perform a systematic analysis of an extension of the Standard Model that
includes a complex singlet scalar field and is scale invariant at the tree
level. We call such a model the Minimal Scale Invariant extension of the
Standard Model (MSISM). The tree-level scale invariance of the model is
explicitly broken by quantum corrections, which can trigger electroweak
symmetry breaking and potentially provide a mechanism for solving the gauge
hierarchy problem. Even though the scale invariant Standard Model is not a
realistic scenario, the addition of a complex singlet scalar field may result
in a perturbative and phenomenologically viable theory. We present a complete
classification of the flat directions which may occur in the classical scalar
potential of the MSISM. After calculating the one-loop effective potential of
the MSISM, we investigate a number of representative scenarios and determine
their scalar boson mass spectra, as well as their perturbatively allowed
parameter space compatible with electroweak precision data. We discuss the
phenomenological implications of these scenarios, in particular, whether they
realize explicit or spontaneous CP violation, neutrino masses or provide dark
matter candidates. In particular, we find a new minimal scale-invariant model
of maximal spontaneous CP violation which can stay perturbative up to
Planck-mass energy scales, without introducing an unnaturally large hierarchy
in the scalar-potential couplings.Comment: 71 pages, 34 eps figures, numerical error corrected, clarifying
comments adde
Linking Changes in Epithelial Morphogenesis to Cancer Mutations Using Computational Modeling
Most tumors arise from epithelial tissues, such as mammary glands and lobules, and their initiation is associated with the disruption of a finely defined epithelial architecture. Progression from intraductal to invasive tumors is related to genetic mutations that occur at a subcellular level but manifest themselves as functional and morphological changes at the cellular and tissue scales, respectively. Elevated proliferation and loss of epithelial polarization are the two most noticeable changes in cell phenotypes during this process. As a result, many three-dimensional cultures of tumorigenic clones show highly aberrant morphologies when compared to regular epithelial monolayers enclosing the hollow lumen (acini). In order to shed light on phenotypic changes associated with tumor cells, we applied the bio-mechanical IBCell model of normal epithelial morphogenesis quantitatively matched to data acquired from the non-tumorigenic human mammary cell line, MCF10A. We then used a high-throughput simulation study to reveal how modifications in model parameters influence changes in the simulated architecture. Three parameters have been considered in our study, which define cell sensitivity to proliferative, apoptotic and cell-ECM adhesive cues. By mapping experimental morphologies of four MCF10A-derived cell lines carrying different oncogenic mutations onto the model parameter space, we identified changes in cellular processes potentially underlying structural modifications of these mutants. As a case study, we focused on MCF10A cells expressing an oncogenic mutant HER2-YVMA to quantitatively assess changes in cell doubling time, cell apoptotic rate, and cell sensitivity to ECM accumulation when compared to the parental non-tumorigenic cell line. By mapping in vitro mutant morphologies onto in silico ones we have generated a means of linking the morphological and molecular scales via computational modeling. Thus, IBCell in combination with 3D acini cultures can form a computational/experimental platform for suggesting the relationship between the histopathology of neoplastic lesions and their underlying molecular defects
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