30,681 research outputs found
A mathematical morphology approach for a qualitative exploration of drought events in space and time
Drought events occur worldwide and possibly incur severe consequences. Trying to understand and characterize drought events is of considerable importance in order to improve the preparedness for coping with future events. In this paper, we present a methodology that allows for the delineation of drought events by exploiting their spatiotemporal nature. To that end, we apply operators borrowed from mathematical morphology to represent drought events as connected components in space and time. As an illustration, we identify drought events on the basis of a 35-year data set of daily soil moisture values covering mainland Australia. We then extract characteristics reflecting the affected area, duration and intensity from the proposed representation of a drought event in order to illustrate the impact of tuning parameters in the methodology presented. Yet, this paper we refrain from comparing with other drought delineation methods
Searching for the most powerful thermonuclear X-ray bursts with the Neil Gehrels Swift Observatory
We searched for thermonuclear X-ray bursts from Galactic neutron stars in all
event mode data of the Neil Gehrels Swift Observatory collected until March 31,
2018. In particular, we are interested in the intermediate-duration bursts
(shell flashes fueled by thick helium piles) with the ill-understood phenomenon
of strong flux fluctuations. Nine such bursts have been discussed in the
literature to date. Swift is particularly suitable for finding additional
examples. We find and list a total of 134 X-ray bursts; 44 are detected with
BAT only, 41 with XRT only, and 49 with both. Twenty-eight bursts involve
automatic slews. We find 12 intermediate-duration bursts, all detected in
observations involving automatic slews. Five show remarkably long
Eddington-limited phases in excess of 200 s. Five show fluctuations during the
decay phase; four of which are first discussed in the present study. We discuss
the general properties of the fluctuations, considering also 7 literature
cases. In general two types of fluctuations are observed: fast ones, with a
typical timescale of 1 s and up and downward fluctuations of up to 70%, and
slow ones, with a typical timescale of 1 min and only downward fluctuations of
up to 90%. The latter look like partial eclipses because the burst decay
remains visible in the residual emission. We revisit the interpretation of this
phenomenon in the context of the new data set and find that it has not changed
fundamentally despite the expanded data set. It is thought to be due to a
disturbance of the accretion disk by outflowing matter and photons, causing
obscuration and reflection due to Thompson scattering in an orbiting highly
ionized cloud or structure above or below the disk. We discuss in detail the
most pronounced burster SAX J1712.6-3739. One of the bursts from this source is
unusual in that it lasts longer than 5600 s, but does not appear to be a
superburst.Comment: Accepted for publication in Astronomy & Astrophysics, 29 pages, 12
figures. Version 2 has 3 bursts from IGR J17480-2446 re-identified to 2 from
Swift J174805.3-244637 and 1 from EXO 1745-24
Maintained physical activity and physiotherapy in the management of distal upper limb pain â a protocol for a randomised controlled trial (the arm pain trial)
<b>Background</b><p></p>
Distal upper limb pain (pain affecting the elbow, forearm, wrist, or hand) can be non-specific, or can arise from specific musculoskeletal disorders. It is clinically important and costly, the best approach to clinical management is unclear. Physiotherapy is the standard treatment and, while awaiting treatment, advice is often given to rest and avoid strenuous activities, but there is no evidence base to support these strategies. This paper describes the protocol of a randomised controlled trial to determine, among patients awaiting physiotherapy for distal arm pain, (a) whether advice to remain active and maintain usual activities results in a long-term reduction in arm pain and disability, compared with advice to rest; and (b) whether immediate physiotherapy results in a long-term reduction in arm pain and disability, compared with physiotherapy delivered after a seven week waiting list period.<p></p>
<b>Methods/Design</b><p></p>
Between January 2012 and January 2014, new referrals to 14 out-patient physiotherapy departments were screened for potential eligibility. Eligible and consenting patients were randomly allocated to one of the following three groups in equal numbers: 1) advice to remain active, 2) advice to rest, 3) immediate physiotherapy. Patients were and followed up at 6, 13, and 26 weeks post-randomisation by self-complete postal questionnaire and, at six weeks, patients who had not received physiotherapy were offered it at this time. The primary outcome is the proportion of patients free of disability at 26 weeks, as determined by the modified DASH (Disabilities of the Arm, Shoulder and Hand) questionnaire.<p></p>
We hypothesise (a) that advice to maintain usual activities while awaiting physiotherapy will be superior than advice to rest the arm; and (b) that fast-track physiotherapy will be superior to normal (waiting list) physiotherapy. These hypotheses will be examined using an intention-to-treat analysis.<p></p>
<b>Discussion</b><p></p>
Results from this trial will contribute to the evidence base underpinning the clinical management of patients with distal upper limb pain, and in particular, will provide guidance on whether they should be advised to rest the arm or remain active within the limits imposed by their symptoms
Hidden Paths in Zygmunt Baumanâs Sociology: Editorial Introduction
In the immediate aftermath of his death, a number of excellent articles were written that each provide a different door into the vast room of Baumanâs sociology. In the past year or so, there have also been a number of books that have set about providing a more âcritical analysisâ of his work whilst also considering how sociology might look anew and move creatively âbeyond Baumanâ (Blackshaw 2016; Jacobsen ed. 2016; Rattansi 2017). In so doing, these welcome contributions clearly take Baumanâs sociological imagination very seriously and provide useful reference points for both scholars and students seeking a more robust examination of Baumanâs ideas. Each contribution deserves to be read and studied as they provide new and considered insights into Baumanâs legacy for the social sciences and humanities. Throughout the article that follows, we make our own contribution to the curious readerâs deliberations on these debates by shining a light on those aspects of Baumanâs work that may have become somewhat hidden and possibly overlooked in what we see as a growing tendency to focus primarily upon his later writings on âliquid modernityâ. We argue that in order to grasp fully the meaning of Baumanâs writing in the more popular post-2000 phase, it is vital that one understands these earlier foundations of his thought. In this way, we hope that we may go some way to rebalancing the concerns of some contemporary critics
EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes.
Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness
Undersea Lawfare: Can the U.S. Navy Fall Victim to This Asymmetric Warfare Threat?
As the worldâs only superpower, the United States of America finds itself challenged by adversaries who know they cannot confront it directly, toe to toe, on traditional battlefields, or on or under the worldâs oceans. In their attempts to follow Sun Tzuâs instruction to âsubdue the enemy without fighting,â potential adversaries of the United States continuously assess and probe American strengths and weaknesses to identify vulnerabilities for military, political, and industrial exploitation. It is not fully appreciated, assessed, or addressed by American policy makers and warfighters how vulnerable the U.S. military is to the threat of âlawfare,â both international and domestic environmental
Strongly-coupled quantum critical point in an all-in-all-out antiferromagnet
Dimensionality and symmetry play deterministic roles in the laws of Nature.
They are important tools to characterize and understand quantum phase
transitions, especially in the limit of strong correlations between spin,
orbit, charge, and structural degrees of freedom. Using newly-developed,
high-pressure resonant x-ray magnetic and charge diffraction techniques, we
have discovered a quantum critical point in Cd2Os2O7 as the all-in-all-out
(AIAO) antiferromagnetic order is continuously suppressed to zero temperature
and, concomitantly, the cubic lattice structure continuously changes from space
group Fd-3m to F-43m. Surrounded by three phases of different time reversal and
spatial inversion symmetries, the quantum critical region anchors two phase
lines of opposite curvature, with striking departures from a mean-field form at
high pressure. As spin fluctuations, lattice breathing modes, and quasiparticle
excitations interact in the quantum critical region, we argue that they present
the necessary components for strongly-coupled quantum criticality in this
three-dimensional compound
TGRS Observations of Positron Annihilation in Classical Novae
The TGRS experiment on board the Wind spacecraft has many advantages as a sky
monitor --- broad field of view (~2 pi) centered on the south ecliptic pole),
long life (1994-present), and stable low background and continuous coverage due
to Wind's high altitude high eccentricity orbit. The Ge detector has sufficient
energy resolution (3-4 keV at 511 keV) to resolve a cosmic positron
annihilation line from the strong background annihilation line from beta-decays
induced by cosmic ray impacts on the instrument, if the cosmic line is
Doppler-shifted by this amount. Such lines (blueshifted) are predicted from
nucleosynthesis in classical novae. We have searched the entire TGRS database
for 1995-1997 for this line, with negative results. In principle such a search
could yield an unbiased upper limit on the highly-uncertain Galactic nova rate.
We carefully examined the times around the known nova events during this
period, also with negative results. The upper limit on the nova line flux in a
6-hr interval is typically <3.8 E-3 photon/(cm2 s) at 4.6 sigma. We performed
the same analysis for times around the outburst of Nova Vel 1999, obtaining a
worse limit due to recent degradation of the detector response caused by cosmic
ray induced damage.Comment: 5 pp. inc. 3 figs. Proc. 5th Compton Symposium (AIP Conf. Series),
ed. M. McConnell, in pres
Whereâs the Data? Using Data Convincingly in Transdisciplinary Doctoral Research
Aim/Purpose The aim of this paper is to identify some of the issues in writing a transdisciplinary doctoral thesis and to develop strategies for addressing them, particularly focusing on the presentation of data and data analysis. The paper, based on the authorsâ own experience, offers guidance to, and invites further comment from, transdisciplinary doctoral candidates, their supervisors and their examiners, as well as the broader field of interdisciplinary and multidisciplinary researchers. Background The paper uses the authorsâ experience of writing four very different transdisciplinary doctoral theses to examine the diverse responses received from examiners and what this means for the thesis writing process. The theses and examinersâ reports span an array of disciplinary and transdisciplinary epistemologies, ontologies, and world views. Methodology A preliminary review of the examinersâ reports revealed a common concern with the definition of âdataâ and with âdata analysisâ. The examinersâ reports were then more formally coded and thematized. These themes were then used to reflect critically on the four theses, within a broad interpretive framework based on the idea of writing âconvincinglyâ, and in light of current literature on the meaning of âdataâ and the idea and aims of transdisciplinarity. Contribution The paper offers specific strategies for doctoral candidates, their supervisors, and examiners in working with the burgeoning number of doctoral research projects that are now taking place in the transdisciplinary space. Findings Doctoral candidates engaged in transdisciplinary research need to define what they mean by data and make data visible in their research, be creative in their conceptions of data and in how they communicate this to examiners, specify the quality criteria against which they wish their work to be assessed and hold discussions with their supervisors about examiner appointments and briefing, and communicate to examiners the special value of transdisciplinary research and the journey on which it takes the researcher. Our conclusion connects these findings to the development of an emerging concept of transdisciplinary research writing. Recommendations for See below under âRecommendations for Researchersâ (For the purpose of Practitioners this paper, practitioners are the researchers). Recommendations The paper makes the following recommendations for transdisciplinary for Researchers doctoral researchers: âą Make the data visible and argue for the unique or special way in which the data will be used âą Make clear the quality criteria against which you expect the work to be judged âą Be creative and explore the possibilities enabled by a broad interpretation of âdataâ âą Transdisciplinary research is transformative. Communicate this to your examiner. Impact on Society As more complex and âwickedâ problems in the world are increasingly addressed through transdisciplinary research, it is important that doctoral research in this area be encouraged, which continues to develop transdisciplinary theoretical frameworks, methodologies and applications. The strategies proposed in this paper will help to ensure the development of high quality transdisciplinary researchers and a greater understanding of the value of transdisciplinary research in the wider research community. It also draws attention to the potential benefits of similar strategies in multidisciplinary and interdisciplinary research. Future Research Further exploration is needed of how researchers across disciplines can âtalkâ to one another to resolve complex problems, and how the solitary transdisciplinary scholar, such as the doctoral student, can effectively communicate their research contribution to others. These issues could also be explored for multidisciplinary and interdisciplinary research teams
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