1,132 research outputs found
Driving improvements in emerging disease surveillance through locally-relevant capacity strengthening
Emerging infectious diseases (EIDs) threaten the health of people, animals, and crops globally, but our ability to predict their occurrence is limited. Current public health capacity and ability to detect and respond to EIDs is typically weakest in low- and middle-income countries (LMICs). Many known drivers of EID emergence also converge in LMICs. Strengthening capacity for surveillance of diseases of relevance to local populations can provide a mechanism for building the cross-cutting and flexible capacities needed to tackle both the burden of existing diseases and EID threats. A focus on locally relevant diseases in LMICs and the economic, social, and cultural contexts of surveillance can help address existing inequalities in health systems, improve the capacity to detect and contain EIDs, and contribute to broader global goals for development
Transition into adulthood: Tuberous sclerosis complex, S turgeâ W eber syndrome, and R asmussen encephalitis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108590/1/epi12722.pd
Temporal Analysis of the Millisecond X-ray Pulsar SAX J1808.4-3658 During the 2000 Outburst
We report a temporal analysis of the millisecond X-ray Pulsar SAX J1808.4-3658 during the 2000 outburst, observed with RXTE. The observed maximum luminosity was approximately a factor of ten lower than in the other outbursts exhibited by the source, and this low flux level forced us to use a technique based on the Ï2 obtained with an epoch folding search to discriminate between different possible orbital solutions, in order to correct the data for the orbital motion. In the subsequent searches for periodicities we clearly detected the 401Hz pulsation in at least two observations, but in the faintest the pulsed fraction varied from 20 % ca. to the absence of signs of coherent pulsation at all, while the measured flux remained at an almost constat level. This erratic behaviour is discussed in the context of the centrifugal inhibition of accretion
One health research in Northern Tanzania â challenges and progress
East Africa has one of the worldâs fastest growing human populationsâmany of whom are dependent on livestockâas
well as some of the worldâs largest wildlife populations. Humans, livestock, and wildlife often interact closely, intimately
linking human, animal, and environmental health. The concept of One Health captures this interconnectedness, including
the social structures and beliefs driving interactions between species and their environments. East African policymakers
and researchers are recognising and encouraging One Health research, with both groups increasingly playing a leading
role in this subject area. One Health research requires interaction between scientists from different disciplines, such as the
biological and social sciences and human and veterinary medicine. Different disciplines draw on norms, methodologies,
and terminologies that have evolved within their respective institutions and that may be distinct from or in conflict with one
another. These differences impact interdisciplinary research, both around theoretical and methodological approaches and
during project operationalisation. We present experiential knowledge gained from numerous ongoing projects in northern
Tanzania, including those dealing with bacterial zoonoses associated with febrile illness, foodborne disease, and anthrax.
We use the examples to illustrate differences between and within social and biological sciences and between industrialised
and traditional societies, for example, with regard to consenting procedures or the ethical treatment of animals. We
describe challenges encountered in ethical approval processes, consenting procedures, and field and laboratory logistics
and offer suggestions for improvement. While considerable investment of time in sensitisation, communication, and collaboration
is needed to overcome interdisciplinary challenges inherent in One Health research, this can yield great
rewards in paving the way for successful implementation of One Health projects. Furthermore, continued investment in
African institutions and scientists will strengthen the role of East Africa as a world leader in One Health research
Countrywide mapping of shrub forest using multi-sensor data and bias correction techniques
The continual increase of shrub forest in the Swiss Alps over the past few decades impacts biodiversity, forest
succession and the protective function of forests. Therefore, up-to-date and area-wide information on its distribution is of great interest. To detect the shrub forest areas for the whole of Switzerland (41,285 km2), we developed an approach that uses Random Forest (RF), bias correction techniques and data from multiple remote sensing sources. Manual aerial orthoimage interpretation of shrub forest areas was conducted in a non-probabilistic way to derive initial training data. The multi-sensor and open access predictor data included digital terrain and vegetation height models obtained from Airborne Laser Scanning (ALS) and stereo-imagery, as well as Synthetic Aperture Radar (SAR) backscatter from Sentinel-1 and multispectral imagery from Sentinel-2. To mitigate the expected bias due to the training data sampling strategy, two techniques using RF probability estimates were tested to improve mapping accuracy. 1) an iterative and semi-automated active learning technique was used to generate further training data and 2) threshold-moving related object growing was applied. Both techniques facilitated the production of a shrub forest map for the whole of Switzerland at a spatial resolution of 10 m. An accuracy assessment was performed using independent data covering 7640 regularly distributed National Forest Inventory (NFI) plots. We observed the influence of the bias correction techniques and found higher accuracies after each performed iteration. The Mean Absolute Error (MAE) for the predicted shrub forest proportion was reduced from 6.04% to 2.68% while achieving a Mean Bias Error (MBE) of close to 0. The present study underscores the potential of combining multi-sensor data with bias correction techniques to provide cost-effective and accurate countrywide detection of shrub forest. Moreover, the map complements currently available NFI plot sample point data
The Evolution in the Faint-End Slope of the Quasar Luminosity Function
(Abridged) Based on numerical simulations of galaxy mergers that incorporate
black hole (BH) growth, we predict the faint end slope of the quasar luminosity
function (QLF) and its evolution with redshift. Our simulations have yielded a
new model for quasar lifetimes where the lifetime depends on both the
instantaneous and peak quasar luminosities. This motivates a new interpretation
of the QLF in which the bright end consists of quasars radiating at nearly
their peak luminosities, but the faint end is mostly made up of quasars in less
luminous phases of evolution. The faint-end QLF slope is then determined by the
faint-end slope of the quasar lifetime for quasars with peak luminosities near
the observed break. We determine this slope from the quasar lifetime as a
function of peak luminosity, based on a large set of simulations spanning a
wide variety of host galaxy, merger, BH, and ISM gas properties. Brighter peak
luminosity (higher BH mass) systems undergo more violent evolution, and expel
and heat gas more rapidly in the final stages of quasar evolution, resulting in
a flatter faint-end slope (as these objects fall below the observed break in
the QLF more rapidly). Therefore, as the QLF break luminosity moves to higher
luminosities with increasing redshift, implying a larger typical quasar peak
luminosity, the faint-end QLF slope flattens. From the quasar lifetime as a
function of peak luminosity and this interpretation of the QLF, we predict the
faint-end QLF slope and its evolution with redshift in good agreement with
observations. Although BHs grow anti-hierarchically (with lower-mass BHs formed
primarily at lower redshifts), the observed change in slope and differential or
luminosity dependent density evolution in the QLF is completely determined by
the luminosity-dependent quasar lifetime and physics of quasar feedback.Comment: 13 pages, 4 figures, submitted to ApJ (Replacement with minor
revisions and changed sign convention
Precise determination of orbital parameters in system with slowly drifting phases: application to the case of XTE J1807-294
We describe a timing technique that allows obtaining precise orbital parameters of an accreting millisecond pulsar in those cases in which intrinsic variations of the phase delays (caused, for example, by proper variation of the spin frequency) with characteristic time-scale longer than the orbital period do not allow to fit the orbital parameters over a long observation (tens of days). We show under which conditions this method can be applied along with the results obtained applying this method to the 2003 outburst observed by RXTE of the accreting millisecond pulsar XTE J1807-294 which shows in its phase delays a non-negligible erratic behaviour. We refined the orbital parameters of XTE J1807-294 using all the 90 days in which the pulsation is strongly detected and the method applicable. In this way, we obtain the orbital parameters of the source with a precision more than one order of magnitude better than the previous available orbital solution, a precision obtained to date, on accreting millisecond pulsars, only for SAX J1808.4-3658 analysing several outbursts spanning over seven years and with much better statistics
The Blueprint for Rabies Prevention and Control: A Novel Operational Toolkit for Rabies Elimination
Rabies is a prime example of a neglected tropical disease that mostly affects communities suffering from inequitable health care [1]. The false perception that rabies impacts on society are low is due to case under-reporting and limited awareness of the disease burden [2], [3]. Effective tools for elimination of terrestrial rabies are available [4]. While the sustained deployment of these tools has led to some remarkably successful interventions [5], [6], canine rabies continues to claim lives in rabies-endemic countries and areas of re-emergence, where >95% of human deaths occur as a result of bites by rabid domestic dogs [7], [8]. Control programs targeting dogs can effectively reduce the risk of rabies to humans [3], [9]. However, the design and implementation of such programs still pose considerable challenges to local governments, and a lack of easy-to-use guidelines has been identified as an important reason for this
Kinematic Structure of Merger Remnants
We use numerical simulations to study the kinematic structure of remnants
formed from mergers of equal-mass disk galaxies. In particular, we show that
remnants of dissipational mergers, which include the radiative cooling of gas,
star formation, feedback from supernovae, and the growth of supermassive black
holes, are smaller, rounder, have, on average, a larger central velocity
dispersion, and show significant rotation compared to remnants of
dissipationless mergers. The increased rotation speed of dissipational remnants
owes its origin to star formation that occurs in the central regions during the
galaxy merger. We have further quantified the anisotropy, three-dimensional
shape, minor axis rotation, and isophotal shape of each merger remnant, finding
that dissipational remnants are more isotropic, closer to oblate, have the
majority of their rotation along their major axis, and are more disky than
dissipationless remnants. Individual remnants display a wide variety of
kinematic properties. A large fraction of the dissipational remnants are oblate
isotropic rotators. Many dissipational, and all of the dissipationless, are
slowly rotating and anisotropic. The remnants of gas-rich major mergers can
well-reproduce the observed distribution of projected ellipticities, rotation
parameter (V/\sigma)*, kinematic misalignments, Psi, and isophotal shapes. The
dissipationless remnants are a poor match to this data. Our results support the
merger hypothesis for the origin of low-luminosity elliptical galaxies provided
that the progenitor disks are sufficiently gas-rich, however our remnants are a
poor match to the bright ellipticals that are slowly rotating and uniformly
boxy.Comment: 22 pages, 17 figures, accepted to Ap
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