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We present a detailed guide to advanced collisionless fluid models that incorporate kinetic effects into the fluid framework, and that are much closer to the collisionless kinetic description than traditional magnetohydrodynamics. Such fluid models are directly applicable to modelling the turbulent evolution of a vast array of astrophysical plasmas, such as the solar corona and the solar wind, the interstellar medium, as well as accretion disks and galaxy clusters. The text can be viewed as a detailed guide to Landau fluid models and it is divided into two parts. Part 1 is dedicated to fluid models that are obtained by closing the fluid hierarchy with simple (non-Landau fluid) closures. Part 2 is dedicated to Landau fluid closures. Here in Part 1, we discuss the fluid model of Chew–Goldberger–Low (CGL) in great detail, together with fluid models that contain dispersive effects introduced by the Hall term and by the finite Larmor radius corrections to the pressure tensor. We consider dispersive effects introduced by the non-gyrotropic heat flux vectors. We investigate the parallel and oblique firehose instability, and show that the non-gyrotropic heat flux strongly influences the maximum growth rate of these instabilities. Furthermore, we discuss fluid models that contain evolution equations for the gyrotropic heat flux fluctuations and that are closed at the fourth-moment level by prescribing a specific form for the distribution function. For the bi-Maxwellian distribution, such a closure is known as the ‘normal’ closure. We also discuss a fluid closure for the bi-kappa distribution. Finally, by considering one-dimensional Maxwellian fluid closures at higher-order moments, we show that such fluid models are always unstable. The last possible non Landau fluid closure is therefore the ‘normal’ closure, and beyond the fourth-order moment, Landau fluid closures are required.
In Part 2 of our guide to collisionless fluid models, we concentrate on Landau fluid closures. These closures were pioneered by Hammett and Perkins and allow for the rigorous incorporation of collisionless Landau damping into a fluid framework. It is Landau damping that sharply separates traditional fluid models and collisionless kinetic theory, and is the main reason why the usual fluid models do not converge to the kinetic description, even in the long-wavelength low-frequency limit. We start with a brief introduction to kinetic theory, where we discuss in detail the plasma dispersion function
, and the associated plasma response function
. We then consider a one-dimensional (1-D) (electrostatic) geometry and make a significant effort to map all possible Landau fluid closures that can be constructed at the fourth-order moment level. These closures for parallel moments have general validity from the largest astrophysical scales down to the Debye length, and we verify their validity by considering examples of the (proton and electron) Landau damping of the ion-acoustic mode, and the electron Landau damping of the Langmuir mode. We proceed by considering 1-D closures at higher-order moments than the fourth order, and as was concluded in Part 1, this is not possible without Landau fluid closures. We show that it is possible to reproduce linear Landau damping in the fluid framework to any desired precision, thus showing the convergence of the fluid and collisionless kinetic descriptions. We then consider a 3-D (electromagnetic) geometry in the gyrotropic (long-wavelength low-frequency) limit and map all closures that are available at the fourth-order moment level. In appendix A, we provide comprehensive tables with Padé approximants of
up to the eighth-pole order, with many given in an analytic form.
Early irritability predicts a broad spectrum of psychopathology spanning both internalizing and externalizing disorders, rather than any particular disorder or group of disorders (i.e. multifinality). Very few studies, however, have examined the developmental mechanisms by which it leads to such phenotypically diverse outcomes. We examined whether variation in the diurnal pattern of cortisol moderates developmental pathways between preschool irritability and the subsequent emergence of internalizing and externalizing symptoms 9 years later.
When children were 3 years old, mothers were interviewed about children's irritability and completed questionnaires about their children's psychopathology. Six years later, children collected saliva samples at wake-up and bedtime on three consecutive days. Diurnal cortisol patterns were modeled as latent difference scores between evening and morning samples. When children were approximately 12 years old, mothers again completed questionnaires about their children's psychopathology.
Among children with higher levels of irritability at age 3, a steeper diurnal cortisol slope at age 9 predicted greater internalizing symptoms and irritability at age 12, whereas a blunted slope at age 9 predicted greater externalizing symptoms at age 12, adjusting for baseline and concurrent symptoms.
Our results suggest that variation in stress system functioning can predict and differentiate developmental trajectories of early irritability that are relatively more internalizing v. those in which externalizing symptoms dominate in pre-adolescence.
Classic conceptual frameworks explaining the relationship of personality traits to depression include the precursor and predisposition models. The former hypothesizes that depression is predicted by traits alone whereas the latter hypothesizes that stress, together with personality, predicts depression. Dynamic vulnerability models (DVM) expand on these perspectives by incorporating fluctuations in personality over time. The stress generation model provides an alternative view, positing that depression generates stress, creating a self-perpetuating cycle. However, these conceptual models are rarely directly compared.
We tested these models, focusing on neuroticism and stressful life events that the participant may have contributed to, using path analysis in a sample of 550 never-depressed, adolescent females assessed five times over 3 years.
A dynamic precursor model with stress generation was best supported. For the precursor component, neuroticism predicted subsequent depression across four assessment intervals. For the dynamic trait component, stressful life events predicted subsequent neuroticism at three of four intervals. Finally, in line with stress generation, depression consistently predicted subsequent stressful life events, and life events then predicted depression.
Finding support for the DVM is noteworthy, as this is the first comprehensive test of this model. Moreover, results supported integrating stress generation with trait vulnerability. Continued use of integrated approaches and refining the statistical implementation of these theories is necessary to advance understanding of the development of depression.
Farmers, who have to decide which pesticide to use against a particular crop-damaging pest, need to take into account country-specific regulations (e.g. permitted levels of pesticide residues), application instructions and financial considerations. The fact that these data are stored in different locations, sometimes using different terminology or different languages, makes it difficult to gather these data and requires that farmers are familiar with the variety of terms used, which consequently hampers the efficiency and effectiveness of the decision process. To overcome these challenges, a Web application for pest control is proposed to facilitate the integration of information coming from different Internet sources and representing different terminologies by using an ontology. The application is based on a pest-control ontology (formal representations of domain knowledge that can be interpreted by computers) that accounts for various pesticide regulations of different countries to which the crop is exported. In recent years, ontologies have become a major tool for domain knowledge representation and a core component of many knowledge management systems, decision support systems and other intelligent systems, inter alia, in the context of agriculture. The pest-control ontology developed in the current research includes pest-control concepts that have yet to be covered by existing ontologies. It is demonstrated in the specific case of pepper in Israel. The ontology is expressed using Web Ontology Language (OWL) and thus can be shared on the Web and reused by other ontologies and systems. In addition, a comprehensive method for developing and evaluating agricultural ontologies is presented.
What is the function of babbling in language learning? We examined the structure of parental speech as a function of contingency on infants’ non-cry prelinguistic vocalizations. We analyzed several acoustic and linguistic measures of caregivers’ speech. Contingent speech was less lexically diverse and shorter in utterance length than non-contingent speech. We also found that the lexical diversity of contingent parental speech only predicted infant vocal maturity. These findings illustrate a new form of influence infants have over their ambient language in everyday learning environments. By vocalizing, infants catalyze the production of simplified, more easily learnable language from caregivers.
Reward processing deficits have been implicated in the etiology of depression. A blunted reward positivity (RewP), an event-related potential elicited by feedback to monetary gain relative to loss, predicts new onsets and increases in depression symptoms. Etiological models of depression also highlight stressful life events. However, no studies have examined whether stressful life events moderate the effect of the RewP on subsequent depression symptoms. We examined this question during the key developmental transition from childhood to adolescence.
A community sample of 369 children (mean age of 9) completed a self-report measure of depression symptoms. The RewP to winning v. losing was elicited using a monetary reward task. Three years later, we assessed stressful life events occurring in the year prior to the follow-up. Youth depressive symptoms were rated by the children and their parents at baseline and follow-up.
Stressful life events moderated the effect of the RewP on depression symptoms at follow-up such that a blunted RewP predicted higher depression symptoms in individuals with higher levels of stressful life events. This effect was also evident when events that were independent of the youth's behavior were examined separately.
These results suggest that the RewP reflects a vulnerability for depression that is activated by stress.
Introduction: Close to 2 million transgender (trans) individuals live in the United States and Canada. Trans communities frequently report emergency care avoidance and negative health care experiences. Of note, there is currently no research on the paramedic perspective of caring for trans populations. Our objective was to explore paramedic comfort, confidence, and cultural competency in providing emergency care to trans individuals. Methods: A cross-sectional, semi-structured electronic survey was administered by email to paramedics registered with the College of Paramedics of Nova Scotia (n = 1225) from April 9th to May 7th, 2018. The survey included previously validated questions from other medical settings. Three survey reminders were sent at weekly intervals following survey initiation. A 4-point Likert scale and qualitative open-ended questions were included to evaluate paramedic comfort, confidence, and cultural competency. Descriptive statistics were used to describe respondent characteristics. Open ended questions pertaining to paramedic needs were evaluated using constant comparative analyses consisting of open coding to identify themes. Results: Of the 387 paramedics who participated (response rate = 32%), 77.8% (n = 301) worked ground ambulance in a mixed rural/urban location (32.6%, n = 126) within Nova Scotia (94.5%; n = 365). Most respondents were between the ages of 41-50 (29.5%; n = 114), with > 20 years’ experience (25.1%; n = 97), and male sex assigned at birth (56.1%; n = 217). Over half (54.8%; n = 212) identified as cisgender men. The majority (66.1%; n = 256) reported caring for a patient who identified as trans. 74.7% (n = 289) have never had formal education on trans health. Only 4.1% (n = 16) felt very knowledgeable about providing optimal care to trans communities and 26.6% (n = 103) felt very comfortable in providing optimal care. Most (70%; n = 271) were interested in obtaining formal education. 41.9% (n = 162) reported observing transphobia in the work place. Conclusion: The frequency of trans patient contact by paramedics is perceived to be high. Although comfort and knowledge are relatively low and transphobia witnessed in the work place relatively high, there was strong interest and expressed need for education on trans related health.
Paramedics Providing Palliative Care at Home was launched in two provinces, including a new clinical practice guideline, database, and paramedic training. The aim of this study was to evaluate patient/family satisfaction and paramedic comfort and confidence.
In Part A, we gathered perspectives of patients/families via surveys mailed at enrolment and telephone interviews after an encounter. Responses were reported descriptively and by thematic analysis. In Part B, we surveyed paramedics online pre- and 18 months post-launch. Comfort and confidence were scored on a 4-point Likert scale, and attitudes on a 7-point Likert scale, reported as the median (interquartile range [IQR]); analysis with Wilcoxon ranked sum/thematic analysis of free text.
In Part A, 67/255 (30%) enrolment surveys were returned. Three themes emerged: fulfilling wishes, peace of mind, and feeling prepared for emergencies. In 18 post-encounter interviews, four themes emerged: 24/7 availability, paramedic professionalism and compassion, symptom relief, and a plea for program continuation. Thematic saturation was reached with little divergence. In Part B, 235/1255 (18.9%) pre- and 267 (21.3%) post-surveys were completed. Comfort with providing palliative care without transport improved post launch (p = < 0.001) as did confidence in palliative care without transport (p = < 0.001). Respondents strongly agreed that all paramedics should be able to provide basic palliative care.
After implementation of the multifaceted Paramedics Providing Palliative Care at Home Program, paramedics describe palliative care as important and rewarding. The program resulted in high patient/family satisfaction; simply registering provides peace of mind. After an encounter, families particularly noted the compassion and professionalism of the paramedics.
Hannah C Kinney, Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, USA,
Robin L Haynes, Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, USA,
Dawna D Armstrong, Retired Professor Pathology Baylor College of Medicine, Department of Pathology, Houston, USA,
Richard D Goldstein, Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, USA
The terrifying aspect of the sudden infant death syndrome (SIDS) is that it occurs in infants who seem healthy and then die without warning when put down to sleep. SIDS is not typically witnessed and it is surmized that death occurs during sleep, or during one of the many transitions to waking that occur during normal infant sleep-wake cycles (1). Multiple sleep-related mechanisms have been proposed to cause SIDS (1, 2). These mechanisms include suffocation/asphyxiation in the face-down sleep position, central and/or obstructive sleep apnea, impaired-state-dependent responses to hypoxia and/ or hypercarbia, inadequate autoresuscitation, defective autonomic regulation of blood pressure or thermal responses, and abnormal arousal to life-threatening challenges during sleep.
In this chapter, we review the hypothesis and the neuropathologic evidence that SIDS is precipitated by a dentate gyrus-related seizure or a limbic-related instability that involves the central homeostatic network (CHN). We begin with an overview of this hypothesis, and then review our neuropathologic evidence for an epileptiform hippocampal lesion in the brain of a subset of SIDS infants and young children (41-50% respectively) who died suddenly and unexpectedly (3-5). We then consider the putative mechanism whereby dentate lesions cause seizures, the role of the hippocampus as part of the CHN in stress responses (such as the face-down sleep position), and the potential interactions of brainstem serotonergic (5-HT) deficits and the hippocampus in the pathogenesis of sudden death in infants. We conclude with further directions for research into the role of the hippocampus in sudden and unexpected death in early life.
The Limbic Seizure-Related Hypothesis in SIDS
In 1986, Harper suggested that some SIDS deaths may be due to a fatal seizure during sleep that arises in forebrain-limbic-related circuits (6). This hypothesis arose from the recognition of the following inter-related phenomena: limbic regions are particularly susceptible to epileptogenesis; sleep states lower the threshold for seizure; and SIDS is linked to sleep and arousal. Sleep itself is thought to be a precarious state, in part because of the loss of the major “back-up” forebrain systems of waking which influence the final common pathways in the brainstem that mediate central cardiorespiratory function during sleep. Forebrain limbic regions, such as the hippocampus and amygdala, which are part of the CHN, modulate brainstem cardiorespiratory control in a manner influenced by the sleep-waking cycles.
Individual differences in neuroticism, extraversion, and conscientiousness are associated with, and may predict onset of, internalizing disorders. These general traits can be parsed into facets, but there is a surprising paucity of research on facet risk for internalizing disorders. We examined general traits and facets of neuroticism, extraversion, and conscientiousness in predicting first onsets of depressive and anxiety disorders.
A community sample of 550 adolescent females completed general and facet-level personality measures and diagnostic interviews. Interviews were re-administered 18 months later.
First onsets of depressive disorders were predicted by neuroticism, extraversion, and conscientiousness. Facets predicting first onset of depression included depressivity (neuroticism facet) and lower positive emotionality and sociability (extraversion facets). First onsets of generalized anxiety disorder (GAD) were predicted by neuroticism, and particularly the facet of anxiousness. First onsets of social phobia were predicted at the facet level by anxiousness. First onsets of specific phobia were predicted by neuroticism, low conscientiousness, and all neuroticism facets. In multivariate analyses, first onsets of depression were uniquely predicted by depressivity, and onsets of GAD and social phobia were uniquely predicted by anxiousness over and above the general trait of neuroticism.
General traits predict first onsets of depressive and anxiety disorders. In addition, more specific associations are evident at the facet level. Facets can refine our understanding of the links between personality and psychopathology risk, and provide finer-grained targets for personality-informed interventions.
Thin loess deposits on the uplands of the southeastern Colorado Plateau have previously not been well studied. We sampled deposits and soils from trenches on Hatch Point (HP) mesa near Canyonlands National Park, Utah, and from two outcrops in Mesa Verde National Park, Colorado. At HP, the oldest buried unit yielded 2 optically stimulated luminescence (OSL) ages of 10,370 and 7555 yr; the middle unit yielded 10 OSL ages from 6220 to 1385 yr; and the youngest unit had a single age of 1740 yr. At Mesa Verde (MV), three loess units are preserved in the two outcrops we examined; 6 OSL ages range from 51 to 17 ka. At least one buried soil is present between two units with ages of about 50 and 40 ka. The ages of the loess units in both study areas correspond well with OSL-dated dune sands in Canyonlands National Park and with dune sands on Black Mesa, Arizona. Particle-size distribution combined with chemical and magnetic data indicate that HP loess was derived mostly from nearby sandstone sources with a small component of far-traveled atmospheric dust, whereas MV loess was sourced both from the nearby sandstone and the San Juan River and its tributaries.
Norwood palliation for patients with single ventricle heart disease is associated with a significant risk for acute kidney injury, which portends a worse prognosis. We sought to investigate the impact of hybrid stage I palliation (Hybrid) on acute kidney injury risk.
This study is a single-centre prospective case–control study of seven consecutive neonates with single ventricle undergoing Hybrid palliation. Levels of serum creatinine and four novel urinary biomarkers, namely neutrophil gelatinase-associated lipocalin, interleukin-18, liver fatty acid-binding protein, and kidney injury molecule-1, were obtained before and after palliation. Acute kidney injury was defined as a ⩾50% increase in serum creatinine within 48 hours after the procedure. Data were compared with a contemporary cohort of 12 neonates with single ventricle who underwent Norwood palliation.
Patients who underwent Hybrid were more likely to be high-risk candidates (86 versus 25%, p=0.01) compared with those who underwent Norwood. Despite similar preoperative serum creatinine levels, there was a trend towards higher levels of postoperative peak serum creatinine (0.7 [0.63, 0.94] versus 0.56 [0.47, 0.74], p=0.06) and rate of acute kidney injury (67 versus 29%, p=0.17) in the Norwood cohort. Preoperative neutrophil gelatinase-associated lipocalin (58.4 [11, 86.3] versus 6.3 [5, 16.2], p=0.07) and interleukin-18 (30.6 [9.6, 167.2] versus 6.3 [6.3, 16.4], p=0.03) levels were higher in the Hybrid cohort. Nevertheless, longitudinal mixed-effect models demonstrated Hybrid palliation to be a protective factor against increased postoperative levels of neutrophil gelatinase-associated lipocalin (estimate −1.8 [−3.0, −9.0], p<0.001) and liver fatty acid-binding protein (−49.3 [−89.7, −8.8], p=0.018).
In this single-centre case–control study, postoperative acute kidney injury risk did not differ significantly by single ventricle stage I treatment strategy; however, postoperative elevation in novel urinary biomarkers, consistent with subclinical kidney injury, was encountered in the Norwood cohort but not in the Hybrid cohort.
People with pancreatic cancer have poor survival, and management is challenging. Pancreatic cancer patients' perceptions of their care coordination and its association with their outcomes have not been well-studied. Our objective was to determine if perception of care coordination is associated with patient-reported outcomes or survival.
People with pancreatic cancer who were 1–8 months postdiagnosis (52 with completed resection and 58 with no resection) completed a patient-reported questionnaire that assessed their perceptions of care coordination, quality of life, anxiety, and depression using validated instruments. Mean scores for 15 care-coordination items were calculated and then ranked from highest (best experience) to lowest (worst experience). Associations between care-coordination scores (including communication and navigation domains) and patient-reported outcomes and survival were investigated using general linear regression and Cox regression, respectively. All analyses were stratified by whether or not the tumor had been resected.
In both groups, the highest-ranked care-coordination items were: knowing who was responsible for coordinating care, health professionals being informed about their history, and waiting times. The worst-ranked items related to: how often patients were asked about visits with other health professionals and how well they and their family were coping, knowing the symptoms they should monitor, having sufficient emotional help from staff, and access to additional specialist services. For people who had a resection, better communication and navigation scores were significantly associated with higher quality of life and less anxiety and depression. However, these associations were not statistically significant for those with no resection. Perception of cancer care coordination was not associated with survival in either group.
Significance of results:
Our results suggest that, while many core clinical aspects of care are perceived to be done well for pancreatic cancer patients, improvements in emotional support, referral to specialist services, and self-management education may improve patient-reported outcomes.
Behavioral treatments reduce anxiety, yet many older adults may not have access to these efficacious treatments. To address this need, we developed and evaluated the feasibility and acceptability of a video-delivered anxiety treatment for older Veterans. This treatment program, BREATHE (Breathing, Relaxation, and Education for Anxiety Treatment in the Home Environment), combines psychoeducation, diaphragmatic breathing, and progressive muscle relaxation training with engagement in activities.
A mixed methods concurrent study design was used to examine the clarity of the treatment videos. We conducted semi-structured interviews with 20 Veterans (M age = 69.5, SD = 7.3 years; 55% White, Non-Hispanic) and collected ratings of video clarity.
Quantitative ratings revealed that 100% of participants generally or definitely could follow breathing and relaxation video instructions. Qualitative findings, however, demonstrated more variability in the extent to which each video segment was clear. Participants identified both immediate benefits and motivation challenges associated with a video-delivered treatment. Participants suggested that some patients may need encouragement, whereas others need face-to-face therapy.
Quantitative ratings of video clarity and qualitative findings highlight the feasibility of a video-delivered treatment for older Veterans with anxiety. Our findings demonstrate the importance of ensuring patients can follow instructions provided in self-directed treatments and the role that an iterative testing process has in addressing these issues. Next steps include testing the treatment videos with older Veterans with anxiety disorders.
This study establishes the chronological framework of the sedimentary sequence deposited Dead Sea, ICDP 5017-1, Radiocarbon chronology during the past 50 ka at the deepest part of the Dead Sea (the ICDP 5017-1 site), which was recovered by the Dead Sea Deep Drilling Project (DSDDP) under the auspices of the International Continental Scientific Drilling Program (ICDP). The age-depth model is constructed using 38 14C dates of terrestrial plant remains in a composite 150-m-long profile, generated by anchoring 32 marker layers identified in five cores. The sedimentary records at the ICDP 5017-1 site fills gaps in those obtained from the exposed sections at the high margins of the lake, particularly in times of lake-level retreat, and allows for a high-resolution comparison between the lake’s margins and deepest floor.