1,726 research outputs found
Regular spherical dust spacetimes
Physical (and weak) regularity conditions are used to determine and classify
all the possible types of spherically symmetric dust spacetimes in general
relativity. This work unifies and completes various earlier results. The
junction conditions are described for general non-comoving (and non-null)
surfaces, and the limits of kinematical quantities are given on all comoving
surfaces where there is Darmois matching. We show that an inhomogeneous
generalisation of the Kantowski-Sachs metric may be joined to the
Lemaitre-Tolman-Bondi metric. All the possible spacetimes are explicitly
divided into four groups according to topology, including a group in which the
spatial sections have the topology of a 3-torus. The recollapse conjecture (for
these spacetimes) follows naturally in this approach.Comment: Minor improvements, additional references. Accepted by GR
Knowledge Management and the Contextualisation of Intellectual Property Rights in Innovation Systems
Support for this research was provided by Genome Canada through the Ontario Genomics Institute and Genome Alberta © David Castle et al 2010.Peer reviewedPublisher PD
Patterns of postural deformity in non-ambulant people with cerebral palsy: what is the relationship between the direction of scoliosis, direction of pelvic obliquity, direction of windswept hip deformity and side of hip dislocation?
Objective: To investigate: (a) associations between the direction of scoliosis, direction of pelvic obliquity, direction of windswept deformity and side of hip subluxation/dislocation in non-ambulant people with cerebral palsy; and (b) the lateral distribution of these postural asymmetries
Clusters, technological districts and smart specialisation:An empirical analysis of policy implementation challenges
Infraspinatus scapular retraction test: a reliable and practical method to assess infraspinatus strength in overhead athletes with scapular dyskinesis
Background Alteration of normal scapulohumeral rhythm due to the fatigue of scapular-stabilizing muscles induces decrease of rotator cuff strength. In this study we analyzed the interobserver and intraobserver realibility of the infraspinatus strength test (IST) and infraspinatus scapular retraction test (ISRT) in 29 overhead athletes with scapular dykinesis, before and after 6 months of scapular musculature rehabilitation. Materials and methods Subjects with magnetic resonance imaging (MRI) findings of labral injuries (2 cases, 5%) and cuff tears (4 cases, 11%) were excluded. Scapular dyskinesis patterns were evaluated according to Kibler et al. (J Shoulder Elbow Surg 11:550-556, 2002). We found a type I dyskinesis in 24 cases (83%) and a type II in 5 cases (17%). Patients were tested by using IST and ISRT and the maximum infraspinatus strength (kg) was registered by a handheld dynamometer. Changes in shoulder IR were measured by using a standard goniometry. Rehabilitation continued for 6 months and was focused on the restoration of scapular muscular control and balance. We used a paired Student t test for the significance of the force values (alpha = 0.01). Intraclass correlation coefficient (ICC) and standard error (SE) were applied to determine the realibility of repeated values collected within testers and between testers. Results Values of ICC close to 1 at baseline and at 6 months indicated a higher interexaminer and intraexaminer realibility. IST force values registered a significant increase at 6 months for both examiners (P<0.01). The mean difference between IST and ISRT values were not significant at 6 months (P>0.01). The increase of glenohumeral internal rotation was significant at 6 months (P<0.01). Conclusion The good realibility and the easy reproducibility make the ISRT an excellent test to assess patients with infraspinatus weakness due to scapular dyskinesis and address them toward an appropriate program of rehabilitation aimed to restore scapular musculature balance and control. \ua9 The Author(s) 2010
New policies to deal with climate change and other drivers impacting on resilience to flooding in urban areas: The CORFU approach
Copyright © 2011 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Environmental Science and Policy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Environmental Science and Policy, Vol. 14 Issue 7 (2011). DOI: 10.1016/j.envsci.2011.05.008In the context of urban flood management, resilience is equal to resisting, recovering, reflecting and responding. The variety of causes of flooding and their consequences underpin the need for increased and internationally coordinated efforts to enhance technologies and policies for dealing with floods. This paper addresses this issue and presents some novel research ideas related to resilience to flooding in urban areas, which are under development within the EU FP7 project ‘Collaborative research on flood resilience in urban areas’ (CORFU). The approach adopted in this project aims to quantify the cost-effectiveness of resilience measures and integrative and adaptable flood management plans for different scenarios of relevant drivers: urban development, socio-economic trends and climate changes. It is believed that the way in which the different models are being put together, combined with the variability of conditions in case study areas in Asia and in Europe, will ultimately enable more scientifically sound policies for the management of the consequences of urban flooding
A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
Exoplanets orbiting close to their parent stars could lose some fraction of
their atmospheres because of the extreme irradiation. Atmospheric mass loss
primarily affects low-mass exoplanets, leading to suggest that hot rocky
planets might have begun as Neptune-like, but subsequently lost all of their
atmospheres; however, no confident measurements have hitherto been available.
The signature of this loss could be observed in the ultraviolet spectrum, when
the planet and its escaping atmosphere transit the star, giving rise to deeper
and longer transit signatures than in the optical spectrum. Here we report that
in the ultraviolet the Neptune-mass exoplanet GJ 436b (also known as Gliese
436b) has transit depths of 56.3 +/- 3.5% (1 sigma), far beyond the 0.69%
optical transit depth. The ultraviolet transits repeatedly start ~2 h before,
and end >3 h after the ~1 h optical transit, which is substantially different
from one previous claim (based on an inaccurate ephemeris). We infer from this
that the planet is surrounded and trailed by a large exospheric cloud composed
mainly of hydrogen atoms. We estimate a mass-loss rate in the range of
~10^8-10^9 g/s, which today is far too small to deplete the atmosphere of a
Neptune-like planet in the lifetime of the parent star, but would have been
much greater in the past.Comment: Published in Nature on 25 June 2015. Preprint is 28 pages, 12
figures, 2 table
Activity of the DNA minor groove cross-linking agent SG2000 (SJG-136) against canine tumours
BACKGROUND: Cancer is the leading cause of death in older dogs and its prevalence is increasing. There is clearly a need to develop more effective anti-cancer drugs in dogs. SG2000 (SJG-136) is a sequence selective DNA minor groove cross-linking agent. Based on its in vitro potency, the spectrum of in vivo and clinical activity against human tumours, and its tolerability in human patients, SG2000 has potential as a novel therapeutic against spontaneously occurring canine malignancies. RESULTS: In vitro cytotoxicity was assessed using SRB and MTT assays, and in vivo activity was assessed using canine tumour xenografts. DNA interstrand cross-linking (ICL) was determined using a modification of the single cell gel electrophoresis (comet) assay. Effects on cell cycle distribution were assessed by flow cytometry and measurement of γ-H2AX by immunofluorescence and immunohistochemistry. SG2000 had a multi-log differential cytotoxic profile against a panel of 12 canine tumour cell lines representing a range of common tumour types in dogs. In the CMeC-1 melanoma cell line, DNA ICLs increased linearly with dose following a 1 h treatment. Peak ICL was achieved within 1 h and no removal was observed over 48 h. A relationship between DNA ICL formation and cytotoxicity was observed across cell lines. The formation of γ-H2AX foci was slow, becoming evident after 4 h and reaching a peak at 24 h. SG2000 exhibited significant anti-tumour activity against two canine melanoma tumour models in vivo. Anti-tumour activity was observed at 0.15 and 0.3 mg/kg given i.v. either once, or weekly x 3. Dose-dependent DNA ICL was observed in tumours (and to a lower level in peripheral blood mononuclear cells) at 2 h and persisted at 24 h. ICL increased following the second and third doses in a repeated dose schedule. At 24 h, dose dependent γ-H2AX foci were more numerous than at 2 h, and greater in tumours than in peripheral blood mononuclear cells. SG2000-induced H2AX phosphorylation measured by immunohistochemistry showed good correspondence, but less sensitivity, than measurement of foci. CONCLUSIONS: SG2000 displayed potent activity in vitro against canine cancer cell lines as a result of the formation and persistence of DNA ICLs. SG2000 also had significant in vivo antitumour activity against canine melanoma xenografts, and the comet and γ-H2AX foci methods were relevant pharmacodynamic assays. The clinical testing of SG2000 against spontaneous canine cancer is warranted. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12917-015-0534-2) contains supplementary material, which is available to authorized users
Beyond 'Criminology vs. Zemiology': Reconciling crime with social harm
Since its emergence at the start of the twenty-first century, zemiology and the field of harm studies more generally, has borne an ambiguous and, at times, seemingly antipathetic relationship with the better-established field of criminology. Whilst the tension between the perspectives is, at times, overstated, attempts to reconcile the perspectives have also proved problematic, such that, at present, it appears that they risk either becoming polarized into mutually antagonistic projects, or harmonized to the point that zemiology is simply co-opted within criminology. Whilst tempting to view this as nothing more than an academic squabble, it is the central argument put forward in this chapter that the current trend towards either polariziaton or harmonization of the criminological and zemiological projects, risks impoverishing both perspectives, both intellectually and, more fundamentally, in terms of their capacity to effect meaningful social change. To this end, this chapter offers a critical reflection of recent attempts to reconcile the social harm perspective with criminology, focussing in particular on Majid Yar’s attempts to do so using the concept of ‘recognition’ derived from critical theory. It is suggested that such attempts, whilst important in the contribution they make to developing a theory of harm, are necessarily flawed by their reliance on an implicit assumption of a shared conception of harm underpinning both the concept of ‘crime’ and ‘social harm’. By contrast, it is the central argument put forward in this chapter that zemiology and criminology are best understood as divergent normative projects which, whilst sharing many of the same goals with regards to the improvement of the criminal justice system and the tackling of social problems, differ primarily in the means by which they seek to achieve these. Therefore, rather than denying this debate through the collapsing of one perspective into the other, or polarizing them into hostiles camps, it is only by recognising the nature of this debate and fostering dialogue between the perspectives that we can achieve our shared goals and effect meaningful change
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