749 research outputs found
Arctic shipping and polar seaways
Climate change in the Arctic triggered a series of discourses about the opening-up of a previously unreachable region. Navigation remains however difficult in the Arctic, transits are still very limited, as sea-ice still is a major constraint. How did the development policies of both the North West Passage and the Northern Sea Route unfold ? What are the recent trends in Arctic shipping ?
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
Initial results from a field campaign of wake steering applied at a commercial wind farm â Part 1
Wake steering is a form of wind farm control in which turbines use
yaw offsets to affect wakes in order to yield an increase in total energy
production. In this first phase of a study of wake steering at a commercial
wind farm, two turbines implement a schedule of offsets. Results exploring
the observed performance of wake steering are presented and some
first lessons learned. For two closely spaced turbines, an approximate
14 % increase in energy was measured on the downstream turbine over a
10â sector, with a 4 % increase in energy production of the
combined upstreamâdownstream turbine pair. Finally, the influence of
atmospheric stability over the results is explored.</p
Building consensus around the assessment and interpretation of Symbiodiniaceae diversity
Within microeukaryotes, genetic variation and functional variation sometimes accumulate more quickly than morphological differences. To understand the evolutionary history and ecology of such lineages, it is key to examine diversity at multiple levels of organization. In the dinoflagellate family Symbiodiniaceae, which can form endosymbioses with cnidarians (e.g., corals, octocorals, sea anemones, jellyfish), other marine invertebrates (e.g., sponges, molluscs, flatworms), and protists (e.g., foraminifera), molecular data have been used extensively over the past three decades to describe phenotypes and to make evolutionary and ecological inferences. Despite advances in Symbiodiniaceae genomics, a lack of consensus among researchers with respect to interpreting genetic data has slowed progress in the field and acted as a barrier to reconciling observations. Here, we identify key challenges regarding the assessment and interpretation of Symbiodiniaceae genetic diversity across three levels: species, populations, and communities. We summarize areas of agreement and highlight techniques and approaches that are broadly accepted. In areas where debate remains, we identify unresolved issues and discuss technologies and approaches that can help to fill knowledge gaps related to genetic and phenotypic diversity. We also discuss ways to stimulate progress, in particular by fostering a more inclusive and collaborative research community. We hope that this perspective will inspire and accelerate coral reef science by serving as a resource to those designing experiments, publishing research, and applying for funding related to Symbiodiniaceae and their symbiotic partnerships.journal articl
Reduction in school individualized education program (IEP) services during the COVID-19 pandemic
PurposeThe COVID-19 pandemic created novel challenges for school systems and students, particularly students with disabilities. In the shift to remote/distance learning, this report explores the degree to which children with disabilities did not receive the special education and related services defined in their individualized education program (IEP).MethodsPatients attending an outpatient tertiary care center for neurodevelopmental disabilities in Maryland were surveyed on the impact of the pandemic on educational services provision.ResultsNearly half (46%) of respondents qualified for special education and related services through an IEP before the start of the COVID-19 pandemic. Among those with IEPs, 48% attested to reduced frequency and/or duration of special education and/or related services during the pandemic. The reduction was greatest in occupational therapy services (47%), followed physical therapy services (46%), and special education services (34%).ConclusionThis survey of children with disabilities observes a substantial reduction in IEP services reported in their completed surveys. To address the observed reduction in IEP services, we sought additional education for clinicians on the rights of students with disabilities in anticipation of studentsâ re-entry to the classroom. A special education law attorney provided an instructional session on compensatory education and recovery services to prepare clinicians to properly inform parents about their rights and advocate for patients with unmet IEP services during the pandemic
Solar Energetic Particle Spectrum on 13 December 2006 Determined by IceTop
On 13 December 2006 the IceTop air shower array at the South Pole detected a
major solar particle event. By numerically simulating the response of the
IceTop tanks, which are thick Cherenkov detectors with multiple thresholds
deployed at high altitude with no geomagnetic cut-off, we determined the
particle energy spectrum in the energy range 0.6 to 7.6 GeV. This is the first
such spectral measurement using a single instrument with a well defined viewing
direction. We compare the IceTop spectrum and its time evolution with
previously published results and outline plans for improved resolution of
future solar particle spectra.Comment: To appear in Astrophysical Journal Letters, 6 pages, 4 figure
The Problematization of Sexuality among Women Living with HIV and a New Feminist Approach for Understanding and Enhancing Womenâs Sexual Lives
In the context of HIV, womenâs sexual rights and sexual autonomy are important but frequently overlooked and violated. Guided by community voices, feminist theories, and qualitative empirical research, we reviewed two decades of global quantitative research on sexuality among women living with HIV. In the 32 studies we found, conducted in 25 countries and composed mostly of cis-gender heterosexual women, sexuality was narrowly constructed as sexual behaviours involving risk (namely, penetration) and physiological dysfunctions relating to HIV illness, with far less attention given to the fullness of sexual lives in context, including more positive and rewarding experiences such as satisfaction and pleasure. Findings suggest that women experience declines in sexual activity, function, satisfaction, and pleasure following HIV diagnosis, at least for some period. The extent of such declines, however, is varied, with numerous contextual forces shaping womenâs sexual well-being. Clinical markers of HIV (e.g., viral load, CD4 cell count) poorly predicted sexual outcomes, interrupting widely held assumptions about sexuality for women with HIV. Instead, the effects of HIV-related stigma intersecting with inequities related to trauma, violence, intimate relations, substance use, poverty, aging, and other social and cultural conditions primarily influenced the ways in which women experienced and enacted their sexuality. However, studies framed through a medical lens tended to pathologize outcomes as individual âproblems,â whereas others driven by a public health agenda remained primarily preoccupied with protecting the public from HIV. In light of these findings, we present a new feminist approach for research, policy, and practice toward understanding and enhancing womenâs sexual livesâone that affirms sexual diversity; engages deeply with society, politics, and history; and is grounded in womenâs sexual rights
Searching for VHE gamma-ray emission associated with IceCube neutrino alerts using FACT, H.E.S.S., MAGIC, and VERITAS
The realtime follow-up of neutrino events is a promising approach to search for astrophysical
neutrino sources. It has so far provided compelling evidence for a neutrino point source: the
flaring gamma-ray blazar TXS 0506+056 was observed in coincidence with the high-energy neutrino IceCube-170922A detected by IceCube. The detection of very-high-energy gamma rays (VHE, E > 100 GeV) from this source helped establish the coincidence and constrained the modeling of the blazar emission at the time of the IceCube event. The four major imaging atmospheric Cherenkov telescope arrays (IACTs) - FACT, H.E.S.S., MAGIC, and VERITAS - operate an active follow-up program of target-of-opportunity observations of neutrino alerts sent by IceCube. This program has two main components. One are the observations of known gamma-ray sources around which a cluster of candidate neutrino events has been identified by IceCube (Gamma-ray Follow-Up, GFU). The second one is the follow-up of single high-energy neutrino candidate events of potential astrophysical origin such as IceCube-170922A. GFU has been recently upgraded by IceCube in collaboration with the IACT groups. We present here recent results from the IACT follow-up programs of IceCube neutrino alerts and a description of the upgraded IceCube GFU system
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