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We study the compressible flow dynamics of two-dimensional, steady detonation wave propagation in a high explosive (HE) confined by aluminium (Al) or stainless steel (SS), outside of which is an air layer. We examine how the thickness of the confinement affects the subsonic detonation driving zone structure (DDZ) and the detonation speed
, demonstrating a strong dependence on whether the oblique shock-driven flow in the confiner is supersonic, as for SS, or subsonic, as for Al. A characteristic path analysis is used to examine the information flow from the material boundaries through the supersonic flow regions in both the HE and confiner that can impact the sonic surfaces bounding the subsonic flow regions. It is shown that the nature of gas-dynamic wave reflection off the SS–air or Al–air boundary can significantly influence the DDZ and
Concerns have repeatedly been expressed about the quality of physical healthcare that people with psychosis receive.
To examine whether the introduction of a financial incentive for secondary care services led to improvements in the quality of physical healthcare for people with psychosis.
Longitudinal data were collected over an 8-year period on the quality of physical healthcare that people with psychosis received from 56 trusts in England before and after the introduction of the financial incentive. Control data were also collected from six health boards in Wales where a financial incentive was not introduced. We calculated the proportion of patients whose clinical records indicated that they had been screened for seven key aspects of physical health and whether they were offered interventions for problems identified during screening.
Data from 17 947 people collected prior to (2011 and 2013) and following (2017) the introduction of the financial incentive in 2014 showed that the proportion of patients who received high-quality physical healthcare in England rose from 12.85% to 31.65% (difference 18.80, 95% CI 17.37–20.21). The proportion of patients who received high-quality physical healthcare in Wales during this period rose from 8.40% to 13.96% (difference 5.56, 95% CI 1.33–10.10).
The results of this study suggest that financial incentives for secondary care mental health services are associated with marked improvements in the quality of care that patients receive. Further research is needed to examine their impact on aspects of care that are not incentivised.
We conducted a secondary analysis of data from the National Audit of Psychosis to identify factors associated with use of community treatment orders (CTOs) and assess the quality of care that people on CTOs receive.
Between 1.1 and 20.2% of patients in each trust were being treated on a CTO. Male gender, younger age, greater use of in-patient services, coexisting substance misuse and problems with cognition predicted use of CTOs. Patients on CTOs were more likely to be screened for physical health, have a current care plan, be given contact details for crisis support, and be offered cognitive–behavioural therapy.
CTOs appear to be used as a framework for delivering higher-quality care to people with more complex needs. High levels of variation in the use of CTOs indicate a need for better evidence about the effects of this approach to patient care.
To better understand barriers and facilitators that contribute to antibiotic overuse in long-term care and to use this information to inform an evidence and theory-informed program.
Information on barriers and facilitators associated with the assessment and management of urinary tract infections were identified from a mixed-methods survey and from focus groups with stakeholders working in long-term care. Each barrier or facilitator was mapped to corresponding determinants of behavior change, as described by the theoretical domains framework (TDF). The Rx for Change database was used to identify strategies to address the key determinants of behavior change.
In total, 19 distinct barriers and facilitators were mapped to 8 domains from the TDF: knowledge, skills, environmental context and resources, professional role or identity, beliefs about consequences, social influences, emotions, and reinforcements. The assessment of barriers and facilitators informed the need for a multifaceted approach with the inclusion of strategies (1) to establish buy-in for the changes; (2) to align organizational policies and procedures; (3) to provide education and ongoing coaching support to staff; (4) to provide information and education to residents and families; (5) to establish process surveillance with feedback to staff; and (6) to deliver reminders.
The use of a stepped approach was valuable to ensure that locally relevant barriers and facilitators to practice change were addressed in the development of a regional program to help long-term care facilities minimize antibiotic prescribing for asymptomatic bacteriuria. This stepped approach provides considerable opportunity to advance the design and impact of antimicrobial stewardship programs.
Empirical data on the use of services due to mental health problems in older adults in Europe is lacking. The objective of this study is to identify factors associated with service utilization in the elderly.
As part of the MentDis_ICF65+ study, N = 3,142 people aged 65–84 living in the community in six European and associated countries were interviewed. Based on Andersen's behavioral model predisposing, enabling, and need factors were analyzed with logistic regression analyses.
Overall, 7% of elderly and 11% of those with a mental disorder had used a service due to mental health problems in the last 12 months. Factors significantly associated with underuse were male sex, lower education, living in the London catchment area, higher functional impairment and more comorbid mental disorders. The most frequently reported barrier to service use was personal beliefs, e.g. “I can deal with my problem on my own” (90%).
Underutilization of mental health services among older people in the European community is common and interventions are needed to achieve an adequate use of services.
The dynamics of steady detonation propagation in a two-dimensional, high explosive circular arc geometry are examined computationally using a reactive flow model approach. The arc is surrounded by a low impedance material confiner on its inner surface, while its outer surface is surrounded either by the low impedance confiner or by a high impedance confiner. The angular speed of the detonation and properties of the steady detonation driving zone structure, i.e. the region between the detonation shock and sonic flow locus, are examined as a function of increasing arc thickness for a fixed inner arc radius. For low impedance material confinement on the inner and outer arc surfaces, the angular speed increases monotonically with increasing arc thickness, before limiting to a constant. The limiting behaviour is found to occur when the detonation driving zone detaches from the outer arc surface, leaving a region of supersonic flow on the outer surface. Consequently, the angular speed of the detonation becomes insensitive to further increases in the arc thickness. For high impedance material confinement on the outer arc surface, the observed flow structures are significantly more complex. As the arc thickness increases, we sequentially observe regions of negative shock curvature on the detonation front, reflected shock formation downstream of the reaction zone, and eventually Mach stem formation on the detonation front. Subsequently, a region of supersonic flow develops between the detonation driving zone and the Mach stem structure. For sufficiently wide arcs, the Mach stem structure disappears. For the high impedance material confinement, the angular speed of the detonation first increases with increasing arc thickness, reaches a maximum, decreases, and then limits to a constant for sufficiently large arc thickness. The limiting angular speed is the same as that found for the low impedance confiner on the outer arc surface.
The fluid mechanics of the interaction between a porous material confiner and a steady propagating high explosive (HE) detonation in a two-dimensional slab geometry is investigated through analytical oblique wave polar analysis and multi-material numerical simulation. Two HE models are considered, broadly representing the properties of either a high- or low-detonation-speed HE, which permits studies of detonation propagating at speeds faster or slower than the confiner sound speed. The HE detonation is responsible for driving the compaction front in the confiner, while, in turn, the high material density generated in the confiner as a result of the compaction process can provide a strong confinement effect on the HE detonation structure. Polar solutions that describe the local flow interaction of the oblique HE detonation shock and equilibrium state behind an oblique compaction wave with rapid compaction relaxation rates are studied for varying initial solid volume fractions of the porous confiner. Multi-material numerical simulations are conducted to study the effect of detonation wave driven compaction in the porous confiner on both the detonation propagation speed and detonation driving zone structure. We perform a parametric study to establish how detonation confinement is influenced both by the initial solid volume fraction of the porous confiner and by the time scale of the dynamic compaction relaxation process relative to the detonation reaction time scale, for both the high- and low-detonation-speed HE models. The compaction relaxation time scale is found to have a significant influence on the confinement dynamics, with slower compaction relaxation time scales resulting in more strongly confined detonations and increased detonation speeds. The dynamics of detonation confinement by porous materials when the detonation is propagating either faster or slower than the confiner sound speed is found to be significantly different from that with solid material confiners.
Within acute psychiatric inpatient services, patients exhibiting severely disturbed behaviour can be transferred to a psychiatric intensive care unit (PICU) and/or secluded in order to manage the risks posed to the patient and others. However, whether specific patient groups are more likely to be subjected to these coercive measures is unclear. Using robust methodological and statistical techniques, we aimed to determine the demographic, clinical and behavioural predictors of both PICU and seclusion.
Data were extracted from an anonymised database comprising the electronic medical records of patients within a large South London mental health trust. Two cohorts were derived, (1) a PICU cohort comprising all patients transferred from general adult acute wards to a non-forensic PICU ward between April 2008 and April 2013 (N = 986) and a randomly selected group of patients admitted to general adult wards within this period who were not transferred to PICU (N = 994), and (2) a seclusion cohort comprising all seclusion episodes occurring in non-forensic PICU wards within the study period (N = 990) and a randomly selected group of patients treated in these wards who were not secluded (N = 1032). Demographic and clinical factors (age, sex, ethnicity, diagnosis, admission status and time since admission) and behavioural precursors (potentially relevant behaviours occurring in the 3 days preceding PICU transfer/seclusion or random sample date) were extracted from electronic medical records. Mixed effects, multivariable logistic regression analyses were performed with all variables included as predictors.
PICU cases were significantly more likely to be younger in age, have a diagnosis of bipolar disorder and to be held on a formal section compared with patients who were not transferred to PICU; female sex and longer time since admission were associated with lower odds of transfer. With regard to behavioural precursors, the strongest predictors of PICU transfer were incidents of physical aggression towards others or objects and absconding or attempts to abscond. Secluded patients were also more likely to be younger and legally detained relative to non-secluded patients; however, female sex increased the odds of seclusion. Likelihood of seclusion also decreased with time since admission. Seclusion was significantly associated with a range of behavioural precursors with the strongest associations observed for incidents involving restraint or shouting.
Whilst recent behaviour is an important determinant, patient age, sex, admission status and time since admission also contribute to risk of PICU transfer and seclusion. Alternative, less coercive strategies must meet the needs of patients with these characteristics.
We study the physics of steady detonation wave propagation in a two-dimensional circular arc via a Detonation Shock Dynamics (DSD) surface evolution model. The dependence of the surface angular speed and surface spatial structure on the inner arc radius (
), the arc thickness (
is the outer arc radius) and the degree of confinement on the inner and outer arc is examined. We first analyse the results for a linear
model, in which the normal surface velocity
is the planar Chapman–Jouguet velocity,
is the total surface curvature and
is a length scale representative of a reaction zone thickness. An asymptotic analysis assuming the ratio
is conducted for this model and reveals a complex surface structure as a function of the radial variation from the inner to the outer arc. For sufficiently thin arcs, where
, the angular speed of the surface depends on the inner arc radius, the arc thickness and the inner and outer arc confinement. For thicker arcs, where
, the angular speed does not depend on the outer arc radius or the outer arc confinement to the order calculated. It is found that the leading-order angular speed depends only on
, and corresponds to a Huygens limit (zero curvature) propagation model where
, assuming a constant angular speed and perfect confinement on the inner arc surface. Having the normal surface speed depend on curvature requires the insertion of a boundary layer structure near the inner arc surface. This is driven by an increase in the magnitude of the surface wave curvature as the inner arc surface is approached that is needed to meet the confinement condition on the inner arc surface. For weak inner arc confinement, the surface wave spatial variation with the radial coordinate is described by a triple-deck structure. The first-order correction to the angular speed brings in a dependence on the surface curvature through the parameter
, while the influence of the inner arc confinement on the angular velocity only appears in the second-order correction. For stronger inner arc confinement, the surface wave structure is described by a two-layer solution, where the effect of the confinement on the angular speed is promoted to the first-order correction. We also compare the steady-state arc solution for a PBX 9502 DSD model to an experimental two-dimensional arc geometry validation test.
Geological disposal facilities (GDF) are intended to isolate and contain radioactive waste within multiple protective barriers, deep underground, to ensure that no harmful quantities of radioactivity reach the surface environment. The last line of defense in a multi-barrier GDF is the geosphere, where iron is present in the host rock mineralogy as either Fe(II) or Fe(III), and in groundwater as Fe(II) under reducing conditions. The mobility of risk-driving radionuclides, including uranium and technetium, in the environment is affected significantly by their valence state. Due to its low redox potential, Fe(II) can mediate reduction of these radionuclides from their oxidized, highly mobile, soluble state to their reduced, insoluble state, preventing them from reaching the biosphere. Here a study of five types of potential host rocks, two granitoids, an andesite, a mudstone and a clay-rich carbonate, is reported. The bulk rocks and their minerals were analysed for iron content, Fe(II/III) ratio, and for the speciation and fine-grained nature of alteration product minerals that might have important controls on groundwater interaction. Total iron content varies between 0.9% in clays to 5.6% in the andesite. X-ray absorption spectroscopy reveals that Fe in the granitoids and andesite is predominantly Fe(II), and in mudstones, argillaceous limestone and terrestrial sandstone is predominantly Fe(III). The redox reactivity of the potential host rocks both in the presence and absence of Fe(II)-containing 'model' groundwater was investigated using an azo dye as a probe molecule. Reduction rates as determined by reactivity with the azo dye were correlated with the ability of the rocks to uptake Fe(II) from groundwater rather than with initial Fe(II) content. Potential GDF host rocks must be characterized in terms of mineralogy, texture, grain size and bulk geochemistry to assess how they might interact with groundwater. This study highlights the importance of redox reactivity, not just total iron and Fe(II)/(III) ratio, when considering the host rock performance as a barrier material to limit transport of radionuclides from the GDF.
The importance of social networks for young people who have experienced abuse and neglect remains an underdeveloped area of research and practice. The aim of the study was to investigate the relationship between abuse experienced by children and adolescents and subsequent outcomes on their social support networks. The study sample consisted of 85 clients (aged 8–15) of a service specifically for children reported to child protection due to child abuse and neglect. Abuse was measured using the Harm Consequences Assessment (HCA), which recorded the level of abuse experienced in five domains: Abandonment/No Appropriate Carer, Developmental and Medical Harm, Emotional and Psychological Harm, Physical Harm and Injury, and Sexual Harm. This also ranked abuse experienced in terms of severity: concerning, serious or extreme. Social network was measured using the Social Network Map. Analyses revealed a very high level of abuse for most young people across multiple domains. Social support was most evident in the “other family” category, and a relatively high level of perceived support was reported. There were few significant associations between levels of abuse and social support networks. However, one significant effect evident was for those young people who had not experienced developmental abuse who reported a significantly better network quality in work/school area of life than those who had experienced concerning or serious developmental abuse. This study contributes to an important body of emerging evidence on social support networks for children who have experienced maltreatment.
We summarize the latest results of an ongoing project aimed at connecting starburst galaxies in the local Universe and Lyman-break galaxies (LBGs) in the distant Universe using rest-frame ultraviolet (UV) images. We are quantifying star formation in the local Universe using GALEX data of interacting galaxies and we are using Hubble Space TelescopeU-band and optical images of the Ultra Deep Field to quantify star formation at intermediate (z ~ 1) and high (z > 2) redshifts, respectively. We are measuring sizes of star-forming clumps in all redshift ranges and searching for evolutionary effects. We chose the rest-frame UV to do this work because young and massive stars radiate most their energy in the UV and also because LBGs are selected to be UV-bright. We discuss whether all galaxies go through an LBG phase and whether disks show any sign of size of evolution at z < 1.
V. Ravishankar, Clinical Assistant Professor, Department of Obstetrics, Gynecology, and Reproductive Sciences State University of New York at Stony Brook Stony Brook University School of Medicine Stony Brook, New York,
J. Gerald Quirk, Professor and Chair, Department of Obstetrics, Gynecology, and Reproductive Medicine State University of New York at Stony Brook
This chapter explores the maternal and fetal complications, advances in prenatal diagnosis, and management of complications unique to multiple gestations. Tidal volume and oxygen consumption in multiple gestations are increased, as is the normal alkalosis seen in singleton pregnancy. Hypertensive disorders increase by at least twofold in twin gestations. Hemorrhagic complications occur more frequently with twins. Growth of singletons and twins is comparable until 27 weeks gestation. The uterus accommodates the larger volume imposed by twins by overdistension, and beyond a certain limit, premature labor can result. Preterm deliveries (less than 37 weeks' gestation) occurred in 10.6% of singleton pregnancies against a phenomenal rate of 61.2% of live births in multiple gestations. Diagnosis of multiple gestations, establishing chorionicity, identifying anomalies, foreseeing possible maternal and fetal complications, prevention and treatment of preterm labor, and management of growth restriction are some of the areas of medicolegal concerns in multiple gestations.
Reinaldo Figueroa, Clinical Associate Professor, Department of Obstetrics, Gynecology and Reproductive Medicine State University of New York at Stony Brook,
J. Gerald Quirk, Professor and Chair, Department of Obstetrics, Gynecology, and Reproductive Medicine State University of New York at Stony Brook
Anxiety disorders are commonly treated with exposure-based therapies that rely on extinction of conditioned fear. Persistent fear and anxiety following exposure therapy could reflect a deficit in the recall of extinction learning. Animal models of fear learning have elucidated a neural circuit for extinction learning and recall that includes the amygdala, ventromedial prefrontal cortex (vmPFC), and hippocampus. Whereas the amygdala is important for extinction learning, the vmPFC is a site of neural plasticity that allows for the inhibition of fear during extinction recall. We suggest that the vmPFC receives convergent information from other brain regions, such as contextual information from the hippocampus, to determine the circumstances under which extinction or fear will be recalled. Imaging studies of human fear conditioning and extinction lend credence to this extinction network. Understanding the neural circuitry underlying extinction recall will lead to more effective therapies for disorders of fear and anxiety.
Gregory J. Quirk, Professor Department of Physiology, Ponce School of Medicine, Puerto Rico,
Mohammed R. Milad, Instructor Department of Psychiatry, Harvard Medical School; Assistant in Research Department of Psychiatry, Massachusetts General Hospital,
Edwin Santini, Postdoctoral Fellow Department of Pharmacology, Ponce School of Medicine, Puerto Rico,
Kelimer Lebrón, Postdoctoral Fellow Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA
Most people who experience trauma do not develop posttraumatic stress disorder (PTSD). While 75% of adults have had a traumatic experience fulfilling current DSM–IV criteria as potential factors in the development of PTSD, only 12% actually developed PTSD (Breslau & Kessler, 2001). This suggests that the majority of persons are highly resilient in the face of trauma (Charney, 2004). What are the neural mechanisms that allow a person to recover from trauma without enduring effects? Recent work has focused on extinction of classically conditioned fear as a useful animal model of recovery after trauma. In cued fear conditioning, a tone is paired with a mild footshock. After several such pairings, rats learn that the tone predicts the shock and exhibit a range of species-specific fear responses, including freezing and potentiated startle responses (see Rau & Fanselow, this volume). In extinction, the conditioned tone is repeatedly presented without the shock, causing rats to learn that the tone is no longer dangerous. Understanding the neural mechanisms of extinction learning could lead to new treatments for PTSD, given that extinction underlies exposure-based therapies used to treat PTSD (Foa, 2000; Rothbaum & Schwartz, 2002).
EXTINCTION OF FEAR IS NEW LEARNING
While it may be tempting to think that extinction of conditioned fear simply erases the original tone–shock association, substantial behavioral evidence suggests that this is not the case.