1,027 research outputs found
Emerging roles of epigenetic mechanisms in the enduring effects of early-life stress and experience on learning and memory.
Epigenetic mechanisms are involved in programming gene expression throughout development. In addition, they are key contributors to the processes by which early-life experience fine-tunes the expression levels of key neuronal genes, governing learning and memory throughout life. Here we describe the long-lasting, bi-directional effects of early-life experience on learning and memory. We discuss how enriched postnatal experience enduringly augments spatial learning, and how chronic early-life stress results in persistent and progressive deficits in the structure and function of hippocampal neurons. The existing and emerging roles of epigenetic mechanisms in these fundamental neuroplasticity phenomena are illustrated
Biomass burning at Cape Grim: exploring photochemistry using multi-scale modelling
We have tested the ability of a high-resolution chemical transport model
(CTM) to reproduce biomass burning (BB) plume strikes and ozone (O3)
enhancements observed at Cape Grim in Tasmania, Australia, from the Robbins
Island fire. The CTM has also been used to explore the contribution of
near-field BB emissions and background sources to O3 observations
under conditions of complex meteorology. Using atmospheric observations, we
have tested model sensitivity to meteorology, BB emission factors (EFs)
corresponding to low, medium, and high modified combustion efficiency (MCE),
and spatial variability. The use of two different meteorological models
(TAPM–CTM and CCAM–CTM) varied the first (BB1) plume strike time by up to
15 h and the duration of impact between 12 and 36 h, and it varied
the second (BB2) plume duration between 50 and 57 h. Meteorology also
had a large impact on simulated O3, with one model (TAPM–CTM)
simulating four periods of O3 enhancement, while the other model (CCAM)
simulating only one period. Varying the BB EFs, which in turn varied the
non-methane organic compound (NMOC) ∕ oxides of nitrogen (NOx)
ratio, had a strongly non-linear impact on simulated O3
concentration, with either destruction or production of O3 predicted
in different simulations. As shown in previous work (Lawson et al., 2015),
minor rainfall events have the potential to significantly alter EF due to
changes in combustion processes. Models that assume fixed EF for O3
precursor species in an environment with temporally or spatially variable EF
may be unable to simulate the behaviour of important species such as
O3.
TAPM–CTM is used to further explore the contribution of the Robbins Island
fire to the observed O3 enhancements during BB1 and BB2. Overall,
TAPM–CTM suggests that the dominant source of O3 observed at Cape Grim was
aged urban air (age = 2 days), with a contribution of O3 formed
from local BB emissions.
This work shows the importance of assessing model sensitivity to meteorology
and EF and the large impact these variables can have in particular on
simulated destruction or production of O3 in regional atmospheric
chemistry simulations. This work also shows the importance of using models to
elucidate the contribution from different sources to atmospheric composition,
where this is difficult using observations alone
Targeting the MDM2-p53 Pathway in Dedifferentiated Liposarcoma
Dedifferentiated liposarcoma (DDLPS) is an aggressive adipogenic cancer with poor prognosis. DDLPS tumors are only modestly sensitive to chemotherapy and radiation, and there is a need for more effective therapies. Genetically, DDLPS is characterized by a low tumor mutational burden and frequent chromosomal structural abnormalities including amplification of the 12q13-15 chromosomal region and the MDM2 gene, which are defining features of DDLPS. The MDM2 protein is an E3 ubiquitin ligase that targets the tumor suppressor, p53, for proteasomal degradation. MDM2 amplification or overexpression in human malignancies is associated with cell-cycle progression and worse prognosis. The MDM2-p53 interaction has thus garnered interest as a therapeutic target for DDLPS and other malignancies. MDM2 binds p53 via a hydrophobic protein interaction that is easily accessible with synthetic analogues. Multiple agents have been developed, including Nutlins such as RG7112 and small molecular inhibitors including SAR405838 and HDM201. Preclinical in vitro and animal models have shown promising results with MDM2 inhibition, resulting in robust p53 reactivation and cancer cell death. However, multiple early-phase clinical trials have failed to show a benefit with MDM2 pathway inhibition for DDLPS. Mechanisms of resistance are being elucidated, and novel inhibitors and combination therapies are currently under investigation. This review provides an overview of these strategies for targeting MDM2 in DDLPS
Targeting the Molecular and Immunologic Features of Leiomyosarcoma
Leiomyosarcoma (LMS) is a rare, aggressive mesenchymal tumor with smooth muscle differentiation. LMS is one of the most common histologic subtypes of soft tissue sarcoma; it most frequently occurs in the extremities, retroperitoneum, or uterus. LMS often demonstrates aggressive tumor biology, with a higher risk of developing distant metastatic disease than most sarcoma histologic types. The prognosis is poor, particularly in patients with uterine disease, and there is a need for the development of more effective therapies. Genetically, LMS is karyotypically complex and characterized by a low tumor mutational burden, with frequent alterations in TP53, RB1, PTEN, and DNA damage response pathways that may contribute to resistance against immune-checkpoint blockade monotherapy. The LMS immune microenvironment is highly infiltrated with tumor-associated macrophages and tumor-infiltrating lymphocytes, which may represent promising biomarkers. This review provides an overview of the clinical and pathologic behavior of both soft tissue and uterine LMS and summarizes the genomic and immune characteristics of these tumors and how they may provide opportunities for the development of biomarker-based immune therapies
Weak Interaction Studies with 6He
The 6He nucleus is an ideal candidate to study the weak interaction. To this
end we have built a high-intensity source of 6He delivering ~10^10 atoms/s to
experiments. Taking full advantage of that available intensity we have
performed a high-precision measurement of the 6He half-life that directly
probes the axial part of the nuclear Hamiltonian. Currently, we are preparing a
measurement of the beta-neutrino angular correlation in 6He beta decay that
will allow to search for new physics beyond the Standard Model in the form of
tensor currents.Comment: 5 pages, 4 figures, proceedings for the Eleventh Conference on the
Intersections of Particle and Nuclear Physics (CIPANP 2012
Robust Estimators in Generalized Pareto Models
This paper deals with optimally-robust parameter estimation in generalized
Pareto distributions (GPDs). These arise naturally in many situations where one
is interested in the behavior of extreme events as motivated by the
Pickands-Balkema-de Haan extreme value theorem (PBHT). The application we have
in mind is calculation of the regulatory capital required by Basel II for a
bank to cover operational risk. In this context the tail behavior of the
underlying distribution is crucial. This is where extreme value theory enters,
suggesting to estimate these high quantiles parameterically using, e.g. GPDs.
Robust statistics in this context offers procedures bounding the influence of
single observations, so provides reliable inference in the presence of moderate
deviations from the distributional model assumptions, respectively from the
mechanisms underlying the PBHT.Comment: 26pages, 6 figure
Possibilities for pedagogy in Further Education: Harnessing the abundance of literacy
In this report, it is argued that the most salient factor in the contemporary communicative landscape is the sheer abundance and diversity of possibilities for literacy, and that the extent and nature of students' communicative resources is a central issue in education. The text outlines the conceptual underpinnings of the Literacies for Learning in Further Education project in a social view of literacy, and the associated research design, methodology and analytical framework. It elaborates on the notion of the abundance of literacies in students' everyday lives, and on the potential for harnessing these as resources for the enhancement of learning. It provides case studies of changes in practice that have been undertaken by further education staff in order to draw upon students' everyday literacy practices on Travel and Tourism and Multimedia courses. It ends with some of the broad implications for conceptualising learning that arise from researching through the lens of literacy practices
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