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The distinct turbulence dynamics and transport modulated by a common seagrass species were investigated experimentally using a flexible surrogate canopy in a refractive-index-matching environment that enabled full optical access. The surrogate seagrass replicated the dynamic behaviour and morphological properties of its natural counterpart. The flows studied were subcritical with Froude numbers $Fr<0.26$ and concerned five Reynolds numbers $Re\in [3.4\times 10^{4}, 1.1\times 10^{5}]$ and Cauchy numbers $Ca\in [120, 1200]$. Complementary rigid canopy experiments were also included to aid comparative insight. The flow was quantified in wall-normal planes in a developed region using high-frame-rate particle image velocimetry. Results show that the deflection and coordinated waving motion of the blades redistributed the Reynolds stresses above and below the canopy top. Critically, in-canopy turbulence associated with the seagrass lacked periodic stem wake vortex shedding present in the rigid canopy, yet the flexible canopy induced vortex shedding from the blade tips. Inspection of spatial and temporal characteristics of coherent flow structures using spectral proper orthogonal decomposition reveals that Kelvin–Helmholtz-type vortices are the dominant flow structures associated with the waving motion of the seagrass and that modulated the local flow exchange in both rigid and flexible canopies. A barrier-like effect produced by the blade deflections blocked large-scale turbulence transport, thereby reducing vortex penetration into the canopy. In addition, we uncovered a transition from sweep-dominated to ejection-dominated behaviour in the surrogate seagrass. We hypothesise that the vortices created during the upward blade motion period play a major role in the sweep-to-ejection-dominated transition. Conditionally averaged quadrant analysis on the downward and upward blade motion supports this contention.
This paper reports on a novel measure, attitudes toward genomics and precision medicine (AGPM), which evaluates attitudes toward activities such as genetic testing, collecting information on lifestyle, and genome editing – activities necessary to achieve the goals of precision medicine.
Discussion:
The AGPM will be useful for researchers who want to explore attitudes toward genomics and precision medicine. The association of concerns about precision medicine activities with demographic variables such as religion and politics, as well as higher levels of education, suggests that further education on genomic and precision activities alone is unlikely to shift AGPM scores significantly.
Methods:
We wrote items to represent psychological and health benefits of precision medicine activities, and concerns about privacy, social justice, harm to embryos, and interfering with nature. We validated the measure through factor analysis of its structure, and testing associations with trust in the health information system and demographic variables such as age, sex, education, and religion.
Results:
The AGPM had excellent alpha reliability (.92) and demonstrated good convergent validity with existing measures. Variables most strongly associated with higher levels of concern with precision medicine activities included: regular religious practice, republican political leanings, and higher levels of education.
Participants and research professionals often overestimate how well participants understand and appreciate consent information for clinical trials, and experts often vary in their determinations of participant’s capacity to consent to research. Past research has developed and validated instruments designed to assess participant understanding and appreciation, but the frequency with which they are utilized is unknown.
Methods:
We administered a survey to clinical researchers working with older adults or those at risk of cognitive impairment (N = 1284), supplemented by qualitative interviews (N = 60).
Results:
We found that using a validated assessment of consent is relatively uncommon, being used by only 44% of researchers who had an opportunity. Factors that predicted adoption of validated assessments included not seeing the study sponsor as a barrier, positive attitudes toward assessments, and being confident that they had the resources needed to implement an assessment. The perceived barriers to adopting validated assessments of consent included lack of awareness, lack of knowledge, being unsure of how to administer such an assessment, and the burden associated with implementing this practice.
Conclusions:
Increasing the use of validated assessments of consent will require educating researchers on the practice and emphasizing very practical assessments, and may require Institutional Review Boards (IRBs) or study sponsors to champion the use of assessments.
The propagation of wave disturbances in water of varying depth bounded above by ice sheets is discussed, accounting for gravity, compressibility and elasticity effects. Considering the more realistic scenario of elastic ice sheets reveals a continuous spectrum of acoustic–gravity modes that propagate even below the cutoff frequency of the rigid surface solution where surface (gravity) waves cannot exist. The balance between gravitational forces and oscillations in the ice sheet defines a new dimensionless quantity $\mathfrak{Ka}$. When the ice sheet is relatively thin and the prescribed frequency is relatively low ($\mathfrak{Ka}\ll 1$), the free-surface bottom-pressure solution is retrieved in full. However, thicker ice sheets or propagation of relatively higher frequency modes ($\mathfrak{Ka}\gg 1$) alter the solution fundamentally, which is reflected in an amplified asymmetric signature and different characteristics of the eigenvalues, such that the bottom pressure is amplified when acoustic–gravity waves are transmitted to shallower waters. To analyse these scenarios, an analytical solution and a depth-integrated equation are derived for the cases of constant and varying depths, respectively. Together, these are capable of modelling realistic ocean geometries and an inhomogeneous distribution of ice sheets.
A companion basis for a quiver Γ mutation equivalent to a simply-laced Dynkin quiver is a subset of the associated root system which is a $\mathbb{Z}$-basis for the integral root lattice with the property that the non-zero inner products of pairs of its elements correspond to the edges in the underlying graph of Γ. It is known in type A (and conjectured for all simply-laced Dynkin cases) that any companion basis can be used to compute the dimension vectors of the finitely generated indecomposable modules over the associated cluster-tilted algebra. Here, we present a procedure for explicitly constructing a companion basis for any quiver of mutation type A or D.
The disappearance of Sir John Franklin's Arctic expedition of 1845 led to many rescue attempts, some by the British government and some by private individuals, as well as a large number of works recounting these expeditions and reflecting on the mystery. Little is known about the author of this 1857 work, James Parsons. He begins this dramatic account by noting that the disappearance of a large and well-equipped party is almost unprecedented in the Arctic: nothing certain was known about Franklin's fate twelve years after the last recorded sighting. Parsons' speculations derive from a knowledge of naval practice, and familiarity with the seas and climate of the Arctic region and the records of earlier expeditions. He offers practical suggestions about a new attempt using steam-boats, but knows that this will be to find out what actually happened, because there could now be no possibility of finding survivors.
The risk of vitamin D insufficiency is increased in persons having limited sunlight exposure and dietary vitamin D. Supplementation compliance might be improved with larger doses taken less often, but this may increase the potential for side effects. The objective of the present study was to determine whether a weekly or weekly/monthly regimen of vitamin D supplementation is as effective as daily supplementation without increasing the risk of side effects. Participants were forty-eight healthy adults who were randomly assigned for 3 months to placebo or one of three supplementation regimens: 50 μg/d (2000 IU/d, analysed dose 70 μg/d), 250 μg/week (10 000 IU/week, analysed dose 331 μg/week) or 1250 μg/week (50 000 IU/week, analysed dose 1544 μg/week) for 4 weeks and then 1250 μg/month for 2 months. Daily and weekly doses were equally effective at increasing serum 25-hydroxyvitamin D, which was significantly greater than baseline in all the supplemented groups after 30 d of treatment. Subjects in the 1250 μg treatment group, who had a BMI >26 kg/m2, had a steady increase in urinary Ca in the first 3 weeks of supplementation, and, overall, the relative risk of hypercalciuria was higher in the 1250 μg group than in the placebo group (P= 0·01). Although vitamin D supplementation remains a controversial issue, these data document that supplementing with ≤ 250 μg/week ( ≤ 10 000 IU/week) can improve or maintain vitamin D status in healthy populations without the risk of hypercalciuria, but 24 h urinary Ca excretion should be evaluated in healthy persons receiving vitamin D3 supplementation in weekly single doses of 1250 μg (50 000 IU).
Suicide prevention is a health service priority. Suicide risk may be
greatest during psychiatric in-patient admission and following
discharge.
Aims
To describe the social and clinical characteristics of a comprehensive
sample of in-patient and post-discharge cases of suicide.
Method
A national clinical survey based on a 4-year (1996–2000) sample of cases
of suicide in England and Wales who had been in recent contact with
mental health services (n=4859).
Results
There were 754 (16%) current in-patients and a further 1100 (23%) had
been discharged from psychiatric in-patient care less than 3 months
before death. Nearly a quarter of the in-patient deaths occurred within
the first 7 days of admission; 236 (31%) occurred on the ward, the
majority by hanging. Post-discharge suicide was most frequent in the
first 2 weeks after leaving hospital; the highest number occurred on the
first day.
Conclusions
Suicide might be prevented among in-patients by improving ward design and
removing fixtures that can be used in hanging. Prevention of suicide
after discharge requires early community follow-up and closer supervision
of high-risk patients.
Suicide prevention is a health service priority but the most effective
approaches to prevention may differ between different patient groups.
Aims
To describe social and clinical characteristics in cases of suicide from
different age and diagnostic groups.
Method
A national clinical survey of a 4-year (1996–2000) sample of cases of
suicide in England and Wales where there had been recent (< 1 year)
contact with mental health services (n=4859).
Results
Deaths of young patients were characterised by jumping from a height or
in front of a vehicle, schizophrenia, personality disorder, unemployment
and substance misuse. In older patients, drowning, depression, living
alone, physical illness, recent bereavement and suicide pacts were more
common. People with schizophrenia were often in-patients and died by
violent means. About athird of people with depressive disorder died
within a year of illness onset. Those with substance dependence or
personality disorder had high rates of disengagement from services.
Conclusions
Prevention measures likely to benefit young people include targeting
schizophrenia, dual diagnosis and loss of service contact; those aimed at
depression, isolation and physical ill-health should have more effect on
elderly people.
Previous studies of people convicted of homicide have used different
definitions of mental disorder.
Aims
To estimate the rate of mental disorder in people convicted of homicide;
to examine the relationship between definitions, verdict and outcome in
court.
Method
A national clinical survey of people convicted of homicide
(n=1594) in England and Wales (1996–1999). Rates of
mental disorder were estimated based on: lifetime diagnosis, mental
illness at the time of the offence, contact with psychiatric services,
diminished responsibility verdict and hospital disposal.
Results
Of the 1594, 545 (34%) had a mental disorder: most had not attended
psychiatric services; 85 (5%) had schizophrenia (lifetime); 164 (10%) had
symptoms of mental illness at the time of the offence; 149 (9%) received
a diminished responsibility verdict and 111 (7%) a hospital disposal –
both were associated with severe mental illness and symptoms of
psychosis.
Conclusions
The findings suggest an association between schizophrenia and conviction
for homicide. Most perpetrators with a history of mental disorder were
not acutely ill or under mental healthcare at the time of the offence.
Some perpetrators receive prison sentences despite having severe mental
illness.
Of the many kinds of music to which composers from German-speaking lands have turned their attention, the Lied, or art song, is surely the most paradoxical. Among those who have fallen under the genre's spell, it is easy to discern fervent if not fanatical zealousness. Among those who have not, it is just as easy to detect bemused bewilderment as to how a musical rendering of a German poem is capable of inducing so profound a response. Suffice it to say, the Lied's fortunes seldom have been static.
The paradoxes do not end here. While Lieder often are thought of as diminutive, given that a great many last but a short time when compared to sonatas, concertos, symphonies, or operas, both the history of German song and the density of expression encountered in many works comprising the genre belie that characterization. Even in some of the most evanescent examples, such as Schubert's Über allen Gipfeln ist Ruh, the timelessness that Goethe compresses into his poem combined with the music underscoring it yield an expansiveness precisely because the song is so short: succinct yes, diminutive no! At once the most private yet universalizing of art forms, the Lied, less than a century ago, stood at the forefront of late Romanticism. Together with orchestral and various types of instrumental music, and later the music dramas of Richard Wagner, it formed part of a Teutonic musical juggernaut widely regarded as without peer. On the eve of World War I, at the peak of the genre’s popularity, song settings of German poetry were to be encountered almost everywhere. In Berlin alone, between 1900 and 1914, according to a recent tally, public song recitals, or Liederabende, averaged some twenty a week and invariably were sold out. The Lied was equally ubiquitous in private performances, especially those sponsored by the artistic, intellectual, and economic elite. As one witness has recalled, “Lieder fitted particularly well into the atmosphere of . . . intimate social gatherings. The poem was generally read before each setting was sung. One could easily lose oneself in the mood produced.”