3,234 research outputs found
Dynamics of coreless vortices and rotation-induced dissipation peak in superfluid films on rotating porous substrates
We analyze dynamics of 3D coreless vortices in superfluid films covering
porous substrates. The 3D vortex dynamics is derived from the 2D dynamics of
the film. The motion of a 3D vortex is a sequence of jumps between neighboring
substrate cells, which can be described, nevertheless, in terms of
quasi-continuous motion with average vortex velocity. The vortex velocity is
derived from the dissociation rate of vortex-antivortex pairs in a 2D film,
which was developed in the past on the basis of the Kosterlitz-Thouless theory.
The theory explains the rotation-induced dissipation peak in torsion-oscillator
experiments on He films on rotating porous substrates and can be used in
the analysis of other phenomena related to vortex motion in films on porous
substrates.Comment: 8 pages, 3 figures submitted to Phys. Rev.
Conserved and unique transcriptional features of pharyngeal arches in the skate (Leucoraja erinacea) and evolution of the jaw
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hirschberger, C., Sleight, V. A., Criswell, K. E., Clark, S. J., & Gillis, J. A. Conserved and unique transcriptional features of pharyngeal arches in the skate (Leucoraja erinacea) and evolution of the jaw. Molecular Biology and Evolution, (2021): msab123, https://doi.org/10.1093/molbev/msab123The origin of the jaw is a long-standing problem in vertebrate evolutionary biology. Classical hypotheses of serial homology propose that the upper and lower jaw evolved through modifications of dorsal and ventral gill arch skeletal elements, respectively. If the jaw and gill arches are derived members of a primitive branchial series, we predict that they would share common developmental patterning mechanisms. Using candidate and RNAseq/differential gene expression analyses, we find broad conservation of dorsoventral patterning mechanisms within the developing mandibular, hyoid and gill arches of a cartilaginous fish, the skate (Leucoraja erinacea). Shared features include expression of genes encoding members of the ventralising BMP and endothelin signalling pathways and their effectors, the joint markers nkx3.2 and gdf5 and pro-chondrogenic transcription factor barx1, and the dorsal territory marker pou3f3. Additionally, we find that mesenchymal expression of eya1/six1 is an ancestral feature of the mandibular arch of jawed vertebrates, while differences in notch signalling distinguish the mandibular and gill arches in skate. Comparative transcriptomic analyses of mandibular and gill arch tissues reveal additional genes differentially expressed along the dorsoventral axis of the pharyngeal arches, including scamp5 as a novel marker of the dorsal mandibular arch, as well as distinct transcriptional features of mandibular and gill arch muscle progenitors and developing gill buds. Taken together, our findings reveal conserved patterning mechanisms in the pharyngeal arches of jawed vertebrates, consistent with serial homology of their skeletal derivatives, as well as unique transcriptional features that may underpin distinct jaw and gill arch morphologies.This work was supported by a Biotechnology and Biological Sciences Research Council Doctoral Training Partnership studentship to CH, by a Wolfson College Junior Research Fellowship and MBL Whitman Early Career Fellowship to VAS, and by a Royal Society
University Research Fellowship (UF130182 and URF\R\191007), Royal Society Research Grant (RG140377) and University of Cambridge Sir Isaac Newton Trust Grant (14.23z) to JAG
Rotation-induced 3D vorticity in 4He superfluid films adsorbed on a porous glass
Detailed study of torsional oscillator experiments under steady rotation up
to 6.28 rad/sec is reported for a 4He superfluid monolayer film formed in 1
micrometer-pore diameter porous glass. We found a new dissipation peak with the
height being in proportion to the rotation speed, which is located to the lower
temperature than the vortex pair unbinding peak observed in the static state.
We propose that 3D coreless vortices ("pore vortices") appear under rotation to
explain this new peak. That is, the new peak originates from dissipation close
to the pore vortex lines, where large superfluid velocity shifts the vortex
pair unbinding dissipation to lower temperature. This explanation is confirmed
by observation of nonlinear effects at high oscillation amplitudes.Comment: 4pages, 5figure
Visions in monochrome: Families, marriage and the individualisation thesis
This paper takes issue with the way in which the individualisation thesis – in which it is assumed that close relationships have become tenuous and fragile - has become so dominant in ‘new’ sociological theorising about family life. Although others have criticised this thesis, in this paper the main criticism derives from empirical research findings carried out with members of transnational families living in Britain whose values and practices do not fit easily with ideas of individualisation. It is argued that we need a much more complex and less linear notion of how families change across generations and in time
Woe from stones: commemoration, identity politics and Estonia's 'War of Monuments'
No abstract available
Why does specialist treatment of breast cancer improve survival? The role of surgical management
A kapwa-infused paradigm in teaching Catholic theology/catechesis in a multireligious classroom in the Philippines
The increasing religious diversity in educational space has raised a legitimate question on how Catholic theology/ catechesis must be taught in Philippine Catholic universities given the institutional mandate to educate students “into the faith of the Church through teaching of Christian doctrine in an organic and systematic way” (Wuerl, 2013, 1). On this note, the paper makes reference to “centered plural- ism” (CP), a positional posture espoused by Georgetown University in dealing with this predicament. In an attempt to (re) appropriate CP into local context, there is a need to explore the Filipino conception of self/others as enveloped within the indigenous concept of kapwa. Hereon, the paper finds that CP is not just feasibly suitable in local context but with kapwa's more inclusive description of the relationship of self and others, a CP‐based teaching paradigm in theology/ catechesis is a promising project in the educational scene of the Philippines
Patients over 65 years with Acute Complicated Calculous Biliary Disease are Treated Differently - Results and Insights from the ESTES Snapshot Audit
Background: Accrued comorbidities are perceived to increase operative risk. Surgeons may offer operative treatments less often to their older patients with acute complicated calculous biliary disease (ACCBD). We set out to capture ACCBD incidence in older patients across Europe and the currently used treatment algorithms.
Methods: The European Society of Trauma and Emergency Surgery (ESTES) undertook a snapshot audit of patients undergoing emergency hospital admission for ACCBD between October 1 and 31 2018, comparing patients under and C 65 years. Mortality, postoperative complications, time to operative intervention, post-acute disposition, and length of hospital stay (LOS) were compared between groups. Within the C 65 cohort, comorbidity burden,mortality, LOS, and disposition outcomes were further compared between patients undergoing operative and non-operative management.
Results: The median age of the 338 admitted patients was 67 years; 185 patients (54.7%) of these were the age of 65 or over. Significantly fewer patients C 65 underwent surgical treatment (37.8% vs. 64.7%, p\0.001). Surgical
complications were more frequent in the C 65 cohort than younger patients, and the mean postoperative LOS was significantly longer. Postoperative mortality was seen in 2.2% of patients C 65 (vs. 0.7%, p = 0.253). However,
operated elderly patients did not differ from non-operated in terms of comorbidity burden, mortality, LOS, or postdischarge rehabilitation need.
Conclusions: Few elderly patients receive surgical treatment for ACCBD. Expectedly, postoperative morbidity, LOS, and the requirement for post-discharge rehabilitation are higher in the elderly than younger patients but do not differ from elderly patients managed non-operatively. With multidisciplinary perioperative optimization, elderly patients may be safely offered optimal treatment.
Trial Registration ClinicalTrials.gov (Trial # NCT03610308)
Myocardial changes on 3T cardiovascular magnetic resonance imaging in response to haemodialysis with fluid removal
Background:
Mapping of left ventricular (LV) native T1 is a promising non-invasive, non-contrast imaging biomarker. Native myocardial T1 times are prolonged in patients requiring dialysis, but there are concerns that the dialysis process and fluctuating fluid status may confound results in this population. We aimed to assess the changes in cardiac parameters on 3T cardiovascular magnetic resonance (CMR) before and after haemodialysis, with a specific focus on native T1 mapping.
Methods:
This is a single centre, prospective observational study in which maintenance haemodialysis patients underwent CMR before and after dialysis (both scans within 24 h). Weight measurement, bio-impedance body composition monitoring, haemodialysis details and fluid intake were recorded. CMR protocol included cine imaging and mapping native T1 and T2.
Results:
Twenty-six participants (16 male, 65 ± 9 years) were included in the analysis. The median net ultrafiltration volume on dialysis was 2.3 L (IQR 1.8, 2.5), resulting in a median weight reduction at post-dialysis scan of 1.35 kg (IQR 1.0, 1.9), with a median reduction in over-hydration (as measured by bioimpedance) of 0.75 L (IQR 0.5, 1.4). Significant reductions were observed in LV end-diastolic volume (− 25 ml, p = 0.002), LV stroke volume (− 13 ml, p = 0.007), global T1 (21 ms, p = 0.02), global T2 (− 1.2 ms, p = 0.02) following dialysis. There was no change in LV mass (p = 0.35), LV ejection fraction (p = 0.13) or global longitudinal strain (p = 0.22). On linear regression there was no association between baseline over-hydration (as defined by bioimpedance) and global native T1 or global T2, nor was there an association between the change in over-hydration and the change in these parameters.
Conclusions:
Acute changes in cardiac volumes and myocardial native T1 are detectable on 3T CMR following haemodialysis with fluid removal. The reduction in global T1 suggests that the abnormal native T1 observed in patients on haemodialysis is not entirely due to myocardial fibrosis
Brendan meets Columbus: A more commodious islescape
This paper proposes that we can reimagine insular literatures and medieval islescapes as commodious seas of cultural and intellectual loci that span time, culture, and text alike. By moving beyond the rhetoric of insular separation or connectivity, we can see that islands connect even when medieval minds saw separation. The essay focuses on the Brendan legend and the commodious cultural ‘sea of islands’ that it inhabits, a space that connects the modern reader to a history of other connections, fact to fancy, and the real and the imaginary. When sailing in this sea, Brendan meets Columbus, and the late medieval idea of a lost island spreads though space and time
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