732 research outputs found
Decolonising Philosophy
Based on Maldonado-Torres’s formulation of the term, we conceive the decolonial turn as a form of liberating and decolonising reason beyond the liberal and Enlightened emancipation of rationality, and beyond the more radical Euro-critiques that have failed to consistently challenge the legacies of Eurocentrism and white male heteronormativity (often Eurocentric critiques of Eurocentrism). We complement Maldonado-Torres’s account of the decolonial turn in philosophy, theory and critique by providing an analysis of the trajectories of academic philosophy and clarifying the relevance of decolonising philosophy and of the decolonial turn for current efforts in transforming philosophy in face of the challenges of social movements such as the Third World Liberation Front and Black Lives Matter in the United States, and Rhodes Must Fall in South Africa and England. After a brief analysis of the trajectory and current status of philosophy as a discipline in the modern Western research university, we provide examples of the decolonial turn and of decolonising philosophy in three areas: the engagement with (1) Asian and (2) Latin American philosophies, and (3) debates in the philosophy of race and gender
Planetary Nebulae as Probes of Stellar Evolution and Populations
Planetary Nebulae (PNe) have been used satisfactory to test the effects of
stellar evolution on the Galactic chemical environment. Moreover, a link exists
between nebular morphology and stellar populations and evolution. We present
the latest results on Galactic PN morphology, and an extension to a distance
unbiased and homogeneous sample of Large Magellanic Cloud PNe. We show that PNe
and their morphology may be successfully used as probes of stellar evolution
and populations.Comment: to appear in: Chemical Evolution of the Milky Way: stars versus
clusters, ed. F. Giovannelli and F. Matteucci, Kluwer (2000), in pres
Reviewing, indicating, and counting books for modern research evaluation systems
In this chapter, we focus on the specialists who have helped to improve the
conditions for book assessments in research evaluation exercises, with
empirically based data and insights supporting their greater integration. Our
review highlights the research carried out by four types of expert communities,
referred to as the monitors, the subject classifiers, the indexers and the
indicator constructionists. Many challenges lie ahead for scholars affiliated
with these communities, particularly the latter three. By acknowledging their
unique, yet interrelated roles, we show where the greatest potential is for
both quantitative and qualitative indicator advancements in book-inclusive
evaluation systems.Comment: Forthcoming in Glanzel, W., Moed, H.F., Schmoch U., Thelwall, M.
(2018). Springer Handbook of Science and Technology Indicators. Springer Some
corrections made in subsection 'Publisher prestige or quality
Canine pseudopregnancy: an evaluation of prevalence and current treatment protocols in the UK
Background: There is a dearth of literature on pseudopregnancy in the bitch, with only a few treatment-based
studies published since the 1990s. Pseudopregnancy may be under-recognised in bitches and may account for a
proportion of behavioural cases seen in veterinary practices including aggression. Little is known about commonly
used treatments for overtly pseudopregnant bitches and it is possible that current regimes may not be prescribed
for a sufficient duration to control any clinical signs including, physical and behavioural changes. To investigate
current trends in diagnosis and treatment of canine pseudopregnancy, a postal survey was sent to 2000 randomly
selected veterinary surgeons in UK veterinary practices. The questionnaire queried how often vets recognise cases
of pseudopregnancy in spayed and entire bitches, which physical or behavioural signs are commonly recognised
for diagnosis, and which management or treatment protocols are used.
Results: The response rate was 19.8% (397/2000). Ninety-six percent of veterinary surgeons reported seeing
pseudopregnant bitches showing behavioural changes without any physical changes within the last 12 months.
Of those behavioural changes, collecting and mothering objects was the most frequently reported behavioural
sign (96%). Ninety-seven percent of vets had seen aggression in pseudopregnant bitches. Nevertheless, only 52%
of vets routinely asked owners about behavioural changes during consultations. Forty-nine percent of respondents
reported seeing pseudopregnancy in spayed bitches. The most commonly reported physical sign was enlarged
mammary glands and/or milk production (89%). Treatment options varied (surgical, medical or none) and depended on
duration and severity of physical and behavioural signs, owners’ preference, cost, concurrent disease, drug availability
and previous history.
Conclusions: This is the largest epidemiological study of canine pseudopregnancy in the UK. The prevalence and
severity of clinical signs in dogs with pseudopregnancy are variable and possibly under-estimated. Dogs with overt
pseudopregnancy experience diverse physical and behavioural changes and information on standard treatment
protocols are lacking. Although, progress on our understanding of diagnosis and treatment of pseudopregnancy in
spayed and entire bitches has been made, further studies are warranted
Radiographers supporting radiologists in the interpretation of screening mammography: a viable strategy to meet the shortage in the number of radiologists.
BackgroundAn alternative approach to the traditional model of radiologists interpreting screening mammography is necessary due to the shortage of radiologists to interpret screening mammograms in many countries.MethodsWe evaluated the performance of 15 Mexican radiographers, also known as radiologic technologists, in the interpretation of screening mammography after a 6 months training period in a screening setting. Fifteen radiographers received 6 months standardized training with radiologists in the interpretation of screening mammography using the Breast Imaging Reporting and Data System (BI-RADS) system. A challenging test set of 110 cases developed by the Breast Cancer Surveillance Consortium was used to evaluate their performance. We estimated sensitivity, specificity, false positive rates, likelihood ratio of a positive test (LR+) and the area under the subject-specific Receiver Operating Characteristic (ROC) curve (AUC) for diagnostic accuracy. A mathematical model simulating the consequences in costs and performance of two hypothetical scenarios compared to the status quo in which a radiologist reads all screening mammograms was also performed.ResultsRadiographer's sensitivity was comparable to the sensitivity scores achieved by U.S. radiologists who took the test but their false-positive rate was higher. Median sensitivity was 73.3 % (Interquartile range, IQR: 46.7-86.7 %) and the median false positive rate was 49.5 % (IQR: 34.7-57.9 %). The median LR+ was 1.4 (IQR: 1.3-1.7 %) and the median AUC was 0.6 (IQR: 0.6-0.7). A scenario in which a radiographer reads all mammograms first, and a radiologist reads only those that were difficult for the radiographer, was more cost-effective than a scenario in which either the radiographer or radiologist reads all mammograms.ConclusionsGiven the comparable sensitivity achieved by Mexican radiographers and U.S. radiologists on a test set, screening mammography interpretation by radiographers appears to be a possible adjunct to radiologists in countries with shortages of radiologists. Further studies are required to assess the effectiveness of different training programs in order to obtain acceptable screening accuracy, as well as the best approaches for the use of non-physician readers to interpret screening mammography
Supernova Remnants as Clues to Their Progenitors
Supernovae shape the interstellar medium, chemically enrich their host
galaxies, and generate powerful interstellar shocks that drive future
generations of star formation. The shock produced by a supernova event acts as
a type of time machine, probing the mass loss history of the progenitor system
back to ages of 10 000 years before the explosion, whereas supernova
remnants probe a much earlier stage of stellar evolution, interacting with
material expelled during the progenitor's much earlier evolution. In this
chapter we will review how observations of supernova remnants allow us to infer
fundamental properties of the progenitor system. We will provide detailed
examples of how bulk characteristics of a remnant, such as its chemical
composition and dynamics, allow us to infer properties of the progenitor
evolution. In the latter half of this chapter, we will show how this exercise
may be extended from individual objects to SNR as classes of objects, and how
there are clear bifurcations in the dynamics and spectral characteristics of
core collapse and thermonuclear supernova remnants. We will finish the chapter
by touching on recent advances in the modeling of massive stars, and the
implications for observable properties of supernovae and their remnants.Comment: A chapter in "Handbook of Supernovae" edited by Athem W. Alsabti and
Paul Murdin (18 pages, 6 figures
Swings between rotation and accretion power in a millisecond binary pulsar
It is thought that neutron stars in low-mass binary systems can accrete
matter and angular momentum from the companion star and be spun-up to
millisecond rotational periods. During the accretion stage, the system is
called a low-mass X-ray binary, and bright X-ray emission is observed. When the
rate of mass transfer decreases in the later evolutionary stages, these
binaries host a radio millisecond pulsar whose emission is powered by the
neutron star's rotating magnetic field. This evolutionary model is supported by
the detection of millisecond X-ray pulsations from several accreting neutron
stars and also by the evidence for a past accretion disc in a rotation-powered
millisecond pulsar. It has been proposed that a rotation-powered pulsar may
temporarily switch on during periods of low mass inflow in some such systems.
Only indirect evidence for this transition has hitherto been observed. Here we
report observations of accretion-powered, millisecond X-ray pulsations from a
neutron star previously seen as a rotation-powered radio pulsar. Within a few
days after a month-long X-ray outburst, radio pulses were again detected. This
not only shows the evolutionary link between accretion and rotation-powered
millisecond pulsars, but also that some systems can swing between the two
states on very short timescales.Comment: 43 pages, 9 figures, 4 table. Published by Nature on 26 Sep 2013.
Includes Supplementary information. Minor differences with published version
may exis
Diminution of Voltage Threshold Plays a Key Role in Determining Recruitment of Oculomotor Nucleus Motoneurons during Postnatal Development
The size principle dictates the orderly recruitment of motoneurons (Mns). This principle assumes that Mns of different sizes have a similar voltage threshold, cell size being the crucial property in determining neuronal recruitment. Thus, smaller neurons have higher membrane resistance and require a lower depolarizing current to reach spike threshold. However, the cell size contribution to recruitment in Mns during postnatal development remains unknown. To investigate this subject, rat oculomotor nucleus Mns were intracellularly labeled and their electrophysiological properties recorded in a brain slice preparation. Mns were divided into 2 age groups: neonatal (1–7 postnatal days, n = 14) and adult (20–30 postnatal days, n = 10). The increase in size of Mns led to a decrease in input resistance with a strong linear relationship in both age groups. A well-fitted inverse correlation was also found between input resistance and rheobase in both age groups. However, input resistance versus rheobase did not correlate when data from neonatal and adult Mns were combined in a single group. This lack of correlation is due to the fact that decrease in input resistance of developing Mns did not lead to an increase in rheobase. Indeed, a diminution in rheobase was found, and it was accompanied by an unexpected decrease in voltage threshold. Additionally, the decrease in rheobase co-varied with decrease in voltage threshold in developing Mns. These data support that the size principle governs the recruitment order in neonatal Mns and is maintained in adult Mns of the oculomotor nucleus; but during postnatal development the crucial property in determining recruitment order in these Mns was not the modifications of cell size-input resistance but of voltage threshold
The stellar halo of the Galaxy
Stellar halos may hold some of the best preserved fossils of the formation
history of galaxies. They are a natural product of the merging processes that
probably take place during the assembly of a galaxy, and hence may well be the
most ubiquitous component of galaxies, independently of their Hubble type. This
review focuses on our current understanding of the spatial structure, the
kinematics and chemistry of halo stars in the Milky Way. In recent years, we
have experienced a change in paradigm thanks to the discovery of large amounts
of substructure, especially in the outer halo. I discuss the implications of
the currently available observational constraints and fold them into several
possible formation scenarios. Unraveling the formation of the Galactic halo
will be possible in the near future through a combination of large wide field
photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes.
Full-resolution version available at
http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd
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