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Slender-body theory is utilized to derive an asymptotic approximation to the hydrodynamic drag on an axisymmetric particle that is held fixed in an otherwise uniform stream of an incompressible Newtonian fluid at moderate Reynolds number. The Reynolds number,
, is based on the length of the particle. The axis of rotational symmetry of the particle is collinear with the uniform stream. The drag is expressed as a series in powers of
is the small ratio of the characteristic width to length of the particle; the series is asymptotic for
. The drag is calculated through terms of
, thereby extending the work of Khayat & Cox (J. Fluid Mech., vol. 209, 1989, pp. 435–462) who determined the drag through
. The calculation of the
term is accomplished via the generalized reciprocal theorem (Lovalenti & Brady, J. Fluid Mech., vol. 256, 1993, pp. 561–605). The first dependence of the inertial contribution to the drag on the cross-sectional profile of the particle is at
. Notably, the drag is insensitive to the direction of travel at this order. The asymptotic results are compared to a numerical solution of the Navier–Stokes equations for the case of a prolate spheroid. Good agreement between the two is observed at moderately small values of
, which is surprising given the logarithmic error associated with the asymptotic expansion.
Although financing represents a critical component of health system strengthening and also a defining concern of efforts to move towards universal health coverage, many countries lack the tools and capacity to plan effectively for service scale-up. As part of a multi-country collaborative study (the Emerald project), we set out to develop, test and apply a fully integrated health systems resource planning and health impact tool for mental, neurological and substance use (MNS) disorders.
A new module of the existing UN strategic planning OneHealth Tool was developed, which identifies health system resources required to scale-up a range of specified interventions for MNS disorders and also projects expected health gains at the population level. We conducted local capacity-building in its use, as well as stakeholder consultations, then tested and calibrated all model parameters, and applied the tool to three priority mental and neurological disorders (psychosis, depression and epilepsy) in six low- and middle-income countries.
Resource needs for scaling-up mental health services to reach desired coverage goals are substantial compared with the current allocation of resources in the six represented countries but are not large in absolute terms. In four of the Emerald study countries (Ethiopia, India, Nepal and Uganda), the cost of delivering key interventions for psychosis, depression and epilepsy at existing treatment coverage is estimated at US$ 0.06–0.33 per capita of total population per year (in Nigeria and South Africa it is US$ 1.36–1.92). By comparison, the projected cost per capita at target levels of coverage approaches US$ 5 per capita in Nigeria and South Africa, and ranges from US$ 0.14–1.27 in the other four countries. Implementation of such a package of care at target levels of coverage is expected to yield between 291 and 947 healthy life years per one million populations, which represents a substantial health gain for the currently neglected and underserved sub-populations suffering from psychosis, depression and epilepsy.
This newly developed and validated module of OneHealth tool can be used, especially within the context of integrated health planning at the national level, to generate contextualised estimates of the resource needs, costs and health impacts of scaled-up mental health service delivery.
Introduction: In Canada, major trauma is a healthcare priority and in 2014 was responsible for over 15866 deaths, with a total economic burden of 26.8 billion dollars. Numerous factors influence the likelihood of occurrence and outcome from major trauma, including incident factors, host, EMS response, emergency, surgical and critical care. Traditionally trauma registers contained information that mainly concerning hospital treatment and host factors. This collaborative analysis uses matched data from a Provincial Trauma Research Register and records from a Provincial Ambulance Service. Methods: A retrospective observational (registry) study comparing rural and urban adult and pediatric major trauma patients (Injury Severity Score >15) who were injured in a motor vehicle crash (ICD V20-V99) and presented to a level 1 or level 2 trauma centre by EMS by primary or secondary transfer, between April 2011 and March 2013 in a selected province in Canada. Comparisons of the process care times, and patient disposition, were made in an inclusive trauma system. Results: 108 cases meet the inclusion criteria with 78 considered rural and 30 urban using published definitions. The median response times were 16.2 minutes for rural (95% CI: 13.2 -19.8) and 7.8 minutes for urban (95% CI: 7.2 - 10.5) with 60% and 61% meeting response targets respectively. A greater proportion of urban patients are taken initially to level 3-5 centers and require secondary transfer (45% urban vs 24% rural p=<0.01). Median times intervals to surgical care were double for the urban patients (14 rural vs 32 hrs urban p=<0.01). Conclusion: The majority of serious road traffic collisions occur in rural areas. Although rural patients wait longer for an initial EMS response, more rural patients are taken directly to a level 1 or 2 trauma center. Unexpectedly then rural patients have much shorter times to surgical care. The benefits of an inclusive trauma system should be weighed against the benefits of bypass processes in urban environments where the nearest Emergency Department is not a Level 1 or 2 Trauma Center.
The self-propulsion of a spherical squirmer – a model swimming organism that achieves locomotion via steady tangential movement of its surface – is quantified across the transition from viscously to inertially dominated flow. Specifically, the flow around a squirmer is computed for Reynolds numbers (
) between 0.01 and 1000 by numerical solution of the Navier–Stokes equations. A squirmer with a fixed swimming stroke and fixed swimming direction is considered. We find that fluid inertia leads to profound differences in the locomotion of pusher (propelled from the rear) versus puller (propelled from the front) squirmers. Specifically, pushers have a swimming speed that increases monotonically with
, and efficient convection of vorticity past their surface leads to steady axisymmetric flow that remains stable up to at least
. In contrast, pullers have a swimming speed that is non-monotonic with
. Moreover, they trap vorticity within their wake, which leads to flow instabilities that cause a decrease in the time-averaged swimming speed at large
. The power expenditure and swimming efficiency are also computed. We show that pushers are more efficient at large
, mainly because the flow around them can remain stable to much greater
than is the case for pullers. Interestingly, if unstable axisymmetric flows at large
are considered, pullers are more efficient due to the development of a Hill’s vortex-like wake structure.
Richerson et al. argue that “cultural group selection plays an essential role in explaining human cooperation.” We believe that cooperation came first, making culture and thus cultural group selection possible. Cooperation and culture began – and begins – in mother–infant interaction.
The turkey (Meleagris gallopavo) was independently domesticated in Mesoamerica and the Southwest, the latter as the only case of Native American animal domestication north of Mexico. In the upland (non-desert) portion of the American Southwest, distinctive closely related mtDNA lineages belonging to haplogroup H1 (thought to indicate domestication) occur from ca. 1 A.D. (Basketmaker II period) through early historic times. At many sites, low frequencies of lineages belonging to haplogroup H2 also occur, apparently derived from the local Merriam’s subspecies. We report genetic, stable isotope, and coprolite data from turkey remains recovered at three early sites in SE Utah and SW Colorado dating to the Basketmaker II, III, and early Pueblo II periods. Evidence from these and other early sites indicates that both the H1 and H2 turkeys had a predominantly maize-based diet similar to that of humans; prior to late Pueblo II times, the birds were kept primarily to provide feathers for blankets and ritual uses; and ritualized burials indicate turkeys’ symbolic value. We argue that viewing individuals from the H1 and H2 haplogroups as “domestic” versus “wild” is an oversimplification.
Cannabis use has been reported to be associated with an earlier onset of symptoms in patients with first-episode psychosis, and a worse outcome in those who continue to take cannabis. In general, studies have concentrated on symptoms of psychosis rather than mania. In this study, using a longitudinal design in a large naturalistic cohort of patients with first-episode psychosis, we investigated the relationship between cannabis use, age of presentation to services, daily functioning, and positive, negative and manic symptoms.
Clinical data on 502 patients with first-episode psychosis were collected using the MiData audit database from seven London-based Early Intervention in psychosis teams. Individuals were assessed at two time points – at entry to the service and after 1 year. On each occasion, the Positive and Negative Syndrome Scale, Young Mania Rating Scale and Global Assessment of Functioning Scale disability subscale were rated. At both time points, the use of cannabis and other drugs of abuse in the 6 months preceding each assessment was recorded.
Level of cannabis use was associated with a younger age at presentation, and manic symptoms and conceptual disorganization, but not with delusions, hallucinations, negative symptoms or daily functioning. Cannabis users who reduced or stopped their use following contact with services had the greatest improvement in symptoms at 1 year compared with continued users and non-users. Continued users remained more symptomatic than non-users at follow-up.
Effective interventions for reducing cannabis use may yield significant health benefits for patients with first-episode psychosis.
A buried epitaxial IrSi3 layer has been produced in (111) oriented Si by high dose Ir+- implantation (1 MeV, 1.7× 1017 Ir+/cm2, 550°C) and subsequent annealing (5 h at 1100°C). Transmission electron microscopy and ion channeling show that the hexagonal IrSi3 prefers to form with its (2110) plane oriented parallel to Si(111). while its  direction is parallel to either , , or . Thus, the IrSi3 film is made up of three differently oriented crystals, each occupying about 1/3 of the silicide volume.
A dose of 3.5× 1016 1r+/cm2 leads to the formation of a band of large, isolated precipitates. They have the same epitaxial relationship to Si, but the Si(111) plane is no longer the only one to which the (2110) of IrSi3 is parallel. Instead precipitates are also observed oriented parallel to (111), (111), and (111) in Si in roughly equal numbers. Consequently, there are now 12 possible orientations of lrSi3 crystals. We assume that strain relief and interface area minimization are the main factors suppressing the additional orientations in the continuous lrSi3 films formed by the coalescence of precipitates at higher doses.
While bipolar disorder (BD) is a leading cause of disability, and an important contributor to disability in BD is cognitive impairment, there is little systematic research on the longitudinal course of cognitive function and instrumental activities of daily living (IADLs) in late-life. In this report, we characterize the 2-year course of cognitive function and IADLs in older adults with BD.
We recruited non-demented individuals 50 years and older with BD I or BD II (n = 47) from out-patient clinics or treatment studies at the University of Pittsburgh. Comparator subjects (‘controls’) were 22 individuals of comparable age and education with no psychiatric or neurologic history, but similar levels of cardiovascular disease. We assessed cognitive function and IADLs at baseline, 1- and 2-year time-points. The neuropsychological evaluation comprised 21 well-established and validated tests assessing multiple cognitive domains. We assessed IADLs using a criterion-referenced, performance-based instrument. We employed repeated-measures mixed-effects linear models to examine trajectory of cognitive function. We employed non-parametric tests for analysis of IADLs.
The BD group displayed worse cognitive function in all domains and worse IADL performance than the comparator group at baseline and over follow-up. Global cognitive function and IADLs were correlated at all time-points. The BD group did not exhibit accelerated cognitive decline over 2 years.
Over 2 years, cognitive impairment and associated functional disability of older adults with BD appear to be due to long-standing neuroprogressive processes compounded by normal cognitive aging rather than accelerated cognitive loss in old age.
§ 1. Let L2(0, ∞) denote the Hilbert space of Lebesgue measurable, integrable-square functions on the half-line [0, ∞).
Integral operators of the form
acting on the space L2 (0, ∞) occur in the theory of ordinary differential equations; see for example the book by E. C. Titchmarsh [4; § 2.6]. It is important to establish when operators of this kind are bounded; see the book by A. E. Taylor [3; § 4.1 and §§4.11, 4.12 and § 4.13].
Empty is that philosopher's argument by which no human suffering is therapeutically treated. For just as there is no use in a medical art that does not cast out the sicknesses of bodies, so too there is no use in philosophy, unless it casts out the suffering of the soul.
Epicurus (341–271 BCE)
The goal for a theory of health and social justice is legitimacy in the moral, political, and policy implementation realms.
Jennifer Prah Ruger (2010, p. xii)
What is knowledge good for?
In ancient Greece, ‘philosophy’ meant love (philia) of knowledge (sophia). Had Epicurus spoken the language of modern science he would have said something to the effect that there is no use in our only scientific theory of life unless it is good for something. Indeed, he might have gone on to explain that the ultimate function of our evolved capability for knowledge is therapy; goodness for us, so to speak. Knowledge is information about our material and social environments represented in our bodies. It helps us develop health and well-being and cast out disease and dysfunction, in ourselves and our loved ones. Aristotle and Confucius both used the metaphor of an archer to make the same point: just as it's hard for an archer to hit his mark without a clear view of the target, so too is it hard for our plans to succeed without a clear view of what they are for. Aristotle believed that ‘human flourishing’ should be the target of ethics and governments. As Jennifer Prah Ruger put it in Health and Social Justice, Aristotle believed that human ‘flourishing’ (eudaimonia) should be ‘the end of all political activity’ (2010, p. 45). Ruger's book is an exploration of what a health policy informed by Aristotelian ethics might look like. In his foreword to the book, Nobel Laureate Amartya Sen describes her project as one of shifting the target of public health from ‘good health policy’ to ‘policy good for health’ (p. ix). Ruger accomplishes this shift by emphasising the moral imperative of health. Health is special, she argues, just because it is constitutive of the ultimate aim of politics, human flourishing.
This is all well and good, but as a scientist I have to ask the begged question: why should we care about human flourishing or its constituents, including health? Why should it be the end of all political activity? My own target in what follows is to show how an evolutionary perspective on healthy feelings might contribute to ‘policy good for health’.
Z-contrast scanning transmission electron microscopy (STEM) is a fundamentally new approach to high-resolution imaging which provides unambiguous, compositionally sensitive images on the atomic scale. Such images are intuitively interpretable, even in thick regions of the sample, tremendously simplifying determination of the structure and chemistry of defects and interfaces. To illustrate this, examples are presented of commonly observed planar defects in laser-ablated thin films of YBa2Cu3O7-x. Film/substrate interfaces are shown to be chemically diffuse on the atomic scale and steps or undulations in the substrate need not result in defects in the film. Low-angle grain boundaries are found to be chemically clean, the drastic reductions in critical currents with tilt angle being due to the array of intrinsic structural defects comprising the boundary.
The correlation of low temperature electrical transport with the evolution of heteroepitaxy and morphology for sputtered indium nitride thin films has been studied. A series of indium nitride films were deposited at temperatures ranging from 50 -650 °C by reactive rf magnetron sputtering onto the (00.1) face of sapphire. Above 350 °C, a transition occurs from a continuous morphology, in which grains are in intimate electrical contact, to an open, porous morphology with poor electrical contact. This transition in morphology deeply affects the electrical transport of the semiconductor. At low deposition temperature, the electrical transport is dominated by the relatively weak intergrain scattering leading to films with moderate mobility. As the deposition temperature is raised, the increasingly porous nature of the film leads to a deterioration in electrical mobility. It is proposed here that the relevant physics of these films is analogous to that for granular solids with a distribution of electrical connectivities that suggests a scattering potential dominated by disorder. In fact, the temperature dependence of the resistivity is found to be analogous to that observed in disordered and amorphous materials. In particular, the resistivity is characterized by: 1) A very weak temperature dependence; 2) The observation of a resistance minimum; and, 3) A steep rise in the low temperature (<4K) resistivity that follows a T1/ dependence.
We developed GaAs heteroepitaxy on a Si substrate by metalorganio vapor phase epitaxy (MOVPE) using tertiarybutylarsine (TBAs). When we preheated Si at 1000ºC in the atmosphere including TBAs, a carbide layer was formed on the Si surface. This led to polycrystalline GaAs growth. By carrying out high-temperature preheating in an H2 -only atmosphere and supplying TBAs after the preheating, we have successfully grown single-crystal GaAs with a mirror surface in a process completely free of AsH3.
We investigate the formation of inAs-rich layers at the interface between InP and arsenicbased Ill-V alloys grown by chemical beam epitaxy (CBE). In-situ spectroscopic ellipsometry, low temperature photoluminescence, secondary ion mass spectrometry and transmission electron microscopy were used to characterize the formation of these layers. We present evidence for interfacial layer roughness that depends strongly on growth temperature and on the presence of surface steps, and show that modifications of the interface chemistry and of the gas-switching sequence can reduce interfacial layer thicknesses.