2,917 research outputs found
Molecular analyses of confiscated shark fins reveal shortcomings of CITES implementations in Germany
A three-ton shipment of dry shark fins was examined by German customs in 2017 leading to the confiscation of 405 kg of potential CITES species. We analyzed a subsample of this material (115 specimens) using DNA sequence-based identification and compared results to morphological screening of CITES species. We found a mixture of CITES regulated (4 of 11 species) and unregulated shark species. Our results demonstrate the difficulties of identifying CITES species morphologically in large fin shipments of mixed species composition. Correct identification of CITES species based on morphology alone may be hindered by missing characters or those altered by drying. We therefore suggest random molecular screening as a uniform approach for German customs authorities to check species composition and identify CITES regulated species in transit shipments.publishedVersio
Collective and single cell behavior in epithelial contact inhibition
Control of cell proliferation is a fundamental aspect of tissue physiology
central to morphogenesis, wound healing and cancer. Although many of the
molecular genetic factors are now known, the system level regulation of growth
is still poorly understood. A simple form of inhibition of cell proliferation
is encountered in vitro in normally differentiating epithelial cell cultures
and is known as "contact inhibition". The study presented here provides a
quantitative characterization of contact inhibition dynamics on tissue-wide and
single cell levels. Using long-term tracking of cultured MDCK cells we
demonstrate that inhibition of cell division in a confluent monolayer follows
inhibition of cell motility and sets in when mechanical constraint on local
expansion causes divisions to reduce cell area. We quantify cell motility and
cell cycle statistics in the low density confluent regime and their change
across the transition to epithelial morphology which occurs with increasing
cell density. We then study the dynamics of cell area distribution arising
through reductive division, determine the average mitotic rate as a function of
cell size and demonstrate that complete arrest of mitosis occurs when cell area
falls below a critical value. We also present a simple computational model of
growth mechanics which captures all aspects of the observed behavior. Our
measurements and analysis show that contact inhibition is a consequence of
mechanical interaction and constraint rather than interfacial contact alone,
and define quantitative phenotypes that can guide future studies of molecular
mechanisms underlying contact inhibition
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Effectiveness of a quality improvement collaborative in reducing time to surgery for patients requiring emergency cholecystectomy.
Background:Acute gallstone disease is a high-volume emergency general surgery presentation with wide variations in the quality of care provided across the UK. This controlled cohort evaluation assessed whether participation in a quality improvement collaborative approach reduced time to surgery for patients with acute gallstone disease to fewer than 8 days from presentation, in line with national guidance. Methods:Patients admitted to hospital with acute biliary conditions in England and Wales between 1 April 2014 and 31 December 2017 were identified from Hospital Episode Statistics data. Time series of quarterly activity were produced for the Cholecystectomy Quality Improvement Collaborative (Chole-QuIC) and all other acute National Health Service hospitals (control group). A negative binomial regression model was used to compare the proportion of patients having surgery within 8 days in the baseline and intervention periods. Results:Of 13 sites invited to join Chole-QuIC, 12 participated throughout the collaborative, which ran from October 2016 to January 2018. Of 7944 admissions, 1160 patients had a cholecystectomy within 8 days of admission, a significant improvement (P < 0·050) from baseline performance. This represented a relative change of 1·56 (95 per cent c.i. 1·38 to 1·75), compared with 1·08 for the control group. At the individual site level, eight of the 12 Chole-QuIC sites showed a significant improvement (P < 0·050), with four sites increasing their 8-day surgery rate to over 20 per cent of all emergency admissions, well above the mean of 15·3 per cent for control hospitals. Conclusion:A surgeon-led quality improvement collaborative approach improved care for patients requiring emergency cholecystectomy
Branch Rings, Thinned Rings, Tree Enveloping Rings
We develop the theory of ``branch algebras'', which are infinite-dimensional
associative algebras that are isomorphic, up to taking subrings of finite
codimension, to a matrix ring over themselves. The main examples come from
groups acting on trees.
In particular, for every field k we construct a k-algebra K which (1) is
finitely generated and infinite-dimensional, but has only finite-dimensional
quotients;
(2) has a subalgebra of finite codimension, isomorphic to ;
(3) is prime;
(4) has quadratic growth, and therefore Gelfand-Kirillov dimension 2;
(5) is recursively presented;
(6) satisfies no identity;
(7) contains a transcendental, invertible element;
(8) is semiprimitive if k has characteristic ;
(9) is graded if k has characteristic 2;
(10) is primitive if k is a non-algebraic extension of GF(2);
(11) is graded nil and Jacobson radical if k is an algebraic extension of
GF(2).Comment: 35 pages; small changes wrt previous versio
Elastic deformation of a fluid membrane upon colloid binding
When a colloidal particle adheres to a fluid membrane, it induces elastic
deformations in the membrane which oppose its own binding. The structural and
energetic aspects of this balance are theoretically studied within the
framework of a Helfrich Hamiltonian. Based on the full nonlinear shape
equations for the membrane profile, a line of continuous binding transitions
and a second line of discontinuous envelopment transitions are found, which
meet at an unusual triple point. The regime of low tension is studied
analytically using a small gradient expansion, while in the limit of large
tension scaling arguments are derived which quantify the asymptotic behavior of
phase boundary, degree of wrapping, and energy barrier. The maturation of
animal viruses by budding is discussed as a biological example of such
colloid-membrane interaction events.Comment: 14 pages, 9 figures, REVTeX style, follow-up on cond-mat/021242
Speech rhythm: a metaphor?
Is speech rhythmic? In the absence of evidence for a traditional view that languages strive to coordinate either syllables or stress-feet with regular time intervals, we consider the alternative that languages exhibit contrastive rhythm subsisting merely in the alternation of stronger and weaker elements. This is initially plausible, particularly for languages with a steep ‘prominence gradient’, i.e. a large disparity between stronger and weaker elements; but we point out that alternation is poorly achieved even by a ‘stress-timed’ language such as English, and, historically, languages have conspicuously failed to adopt simple phonological remedies that would ensure alternation. Languages seem more concerned to allow ‘syntagmatic contrast’ between successive units and to use durational effects to support linguistic functions than to facilitate rhythm. Furthermore, some languages (e.g. Tamil, Korean) lack the lexical prominence which would most straightforwardly underpin prominence alternation. We conclude that speech is not incontestibly rhythmic, and may even be antirhythmic. However, its linguistic structure and patterning allow the metaphorical extension of rhythm in varying degrees and in different ways depending on the language, and that it is this analogical process which allows speech to be matched to external rhythms
Steinert's syndrome presenting as anal incontinence: a case report
<p>Abstract</p> <p>Introduction</p> <p>Myotonic dystrophy (MD) or Steinert's syndrome is a rare cause of chronic diarrhea and anal incontinence. In the presence of chronic diarrhea and fecal incontinence with muscle weakness, neuromuscular disorders such as myotonic dystrophy should be considered in the differential diagnosis.</p> <p>Case Presentation</p> <p>We present the case of a 45-year-old Turkish man with Steinert's syndrome, who was not diagnosed until the age of 45.</p> <p>Conclusions</p> <p>In clinical practice, the persistence of diarrhea and fecal incontinence with muscle weakness should suggest that the physician perform an anal manometric study and electromyography. Neuromuscular disorders such as myotonic dystrophy should be considered in the differential diagnosis.</p
Speech-in-noise perception is linked to rhythm production skills in adult percussionists and non-musicians
Speech rhythms guide perception, especially in noise. We recently revealed that percussionists outperform non-musicians in speech-in-noise perception, with better speech-in-noise perception associated with better rhythm discrimination across a range of rhythmic expertise. Here, we consider rhythm production skills, specifically drumming to a beat (metronome or music) and to sequences (metrical or jittered patterns), as well as speech-in-noise perception in adult percussionists and non-musicians. Given the absence of a regular beat in speech, we hypothesise that processing of sequences is more important for speech-in-noise perception than the ability to entrain to a regular beat. Consistent with our hypothesis, we find that the sequence-based drumming measures predict speech-in-noise perception, above and beyond hearing thresholds and IQ, whereas the beat-based measures do not. Outcomes suggest temporal patterns may help disambiguate speech under degraded listening conditions, extending theoretical considerations about speech rhythm to the everyday challenge of listening in noise
The independent group looks at London's west end
In the early 1950s, British culture was dominated by welfare-state visions of urban reconstruction. These projections of a stable civic society were premised on a particular way of looking at and reading the metropolitan environment. At odds with this project, the Independent Group's discussions and collaborative work developed an alternative urban semiology, which found the city to be already rich in visual resources for fashioning a more profound form of social democracy. Soon, this critical engagement would develop in different directions, represented here by Lawrence Alloway's commentary on Piccadilly Circus in his essay 'City Notes' and the London footage inserted by John McHale into his film for the Smithsons' Berlin Hauptstadt project (both 1959). By the end of the 1950s, members of the erstwhile Independent Group had produced two contrasting critical accounts of how the metropolitan centre should be looked at, which challenged the strictures of post-war reconstruction in distinct and conflicting ways. © The Author(s), 2013
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